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Biomedical subjects

J Janssen

Publications and source records attributed to J Janssen.

At least 19 recordsLinked to original sources
PubMed1991

Long-term efficacy of continuous and intermittent use of transdermal nitroglycerin in stable angina pectoris.

To assess efficacy of transdermal nitrate use, a randomized, placebo-controlled trial of continuous and intermittent use of nitroglycerin patches (10 mg/24 hours) was conducted in 127 patients with stable angina pectoris who discontinued exercise testing within 9 minutes because of angina. After a placebo run-in week, baseline (day 0) symptom-limited exercise testing was performed and repeated on day 1 and 14 before and after the administration of 0.5 mg of sublingual nitroglycerin. On day 0, total exercise duration was the same (within narrow limits) in all 3 groups and remained unchanged in the placebo group. On day 1, total exercise duration increased from 406 +/- 115 to 469 +/- 158 seconds (p less than 0.001) in the continuously treated group and from 396 +/- 105 to 475 +/- 171 seconds (p less than 0.001) in the intermittently treated group. In the intermittent group, exercise duration increased slightly to 483 +/- 140 seconds on day 14, and in the continuous group exercise duration decreased to 447 +/- 144 seconds. However, this decrease was not statistically significant. Similar treatment effects were seen for time to 1-mm ST depression. Sublingual nitroglycerin remained effective in all 3 groups and on all days. Eleven actively treated patients and 1 patient taking placebo discontinued the study because of headache. It is concluded that continuous use of transdermal nitroglycerin remains partially effective and intermittent therapy remains fully effective in improving long-term exercise capacity with acceptable adverse effects in patients with stable angina pectoris.

Administration, Cutaneous↗
PubMed1990

[Norplant].

Explore the source record for details and available documents.

Contraceptives, Oral, Combined↗
PubMed1990

Behavioral and neurophysiological assessment of lateral line sensitivity in the mottled sculpin, Cottus bairdi.

1. The unconditioned feeding response of the mottled sculpin, Cottus bairdi, was used to measure threshold sensitivity of the lateral line system to a vibrating sphere as a function of stimulus position (i.e., sphere near head, trunk or tail) and vibration frequency. In addition, extracellular recording techniques were used to measure threshold sensitivity curves for posterior lateral line nerve fibers for the same stimulus positions used for measuring trunk sensitivity in behavioral measurements. 2. For all stimulus positions, behaviorally-measured threshold sensitivity was relatively independent of vibration frequency from 10 to 100 Hz when defined in terms of water acceleration, rather than velocity or displacement. Best thresholds for stimuli placed 15 mm away from the head were around -75 dB re: 1m/s(2), approximately 20 dB less than that for stimuli placed at the same distance near the tail. Trunk sensitivity was intermediate. 3. Physiologically-measured threshold sensitivity, in terms of acceleration, was also relatively independent of of frequency from 10 to 100 Hz in most fibers. A smaller number of fibers showed a decline in acceleration sensitivity after 10-30 Hz, with the rate of decline being equivalent to equal velocity sensitivity. Best sensitivity of all fibers fell between -40 and -70 dB re: 1m/s (2). 4. These results indicate that (a) behavioral thresholds are based on acceleration-sensitive endorgans--most likely lateral line canal (rather than superficial) neuromasts, (b) behavioral performance can be accounted for on the basis of information from a single population of fibers, and (c) sensitivity varies along the fish's body in a manner that corresponds to the size and distribution of neuromasts.

Behavior, Animal↗
PubMed1990

Effect of immunomodulator thymopentin on impaired seroresponse to influenza vaccine in patients on haemodialysis.

In a double-blind placebo-controlled multicentre study, the effect of the immunomodulator thymopentin (TP5) on the antibody production to trivalent influenza vaccine was tested in 108 patients on chronic intermittent haemodialysis (HD). Antibody production was determined in pre- and postvaccination sera. Compared to a group of 35 young healthy adult control subjects, HD patients showed a clearly impaired seroresponsiveness to all three vaccine components, regardless of treatment with TP5 or placebo. We conclude that TP5 administration is not able to enhance humoral immunity in patients on chronic intermittent HD.

Adolescent↗
PubMed1989

Nonischemic sustained ventricular tachycardia: clinical outcome in 12 patients with arrhythmogenic right ventricular dysplasia.

The clinical course and long-term follow-up of 12 patients with arrhythmogenic right ventricular dysplasia causing ventricular tachycardia are presented. No patient had a history of congestive heart failure and the cardiothoracic ratio measured less than or equal to 0.5 in all patients. All 12 patients were symptomatic during ventricular tachycardia; syncope occurred in 4. Exercise-related symptoms were present in 8 (73%) of 11 patients. The mean right ventricular ejection fraction was 31% (range 20% to 54%), and the mean left ventricular ejection fraction was 68% (range 44% to 88%). Signal averaging of the rest electrocardiogram (ECG) revealed late potentials in five of eight patients. During programmed electrical stimulation, sustained or nonsustained ventricular tachycardia showing a left bundle branch block configuration was induced in all patients. One patient underwent right ventricular disconnection and died 1 week after operation of low cardiac output failure. The remaining 11 patients were all treated medically and are alive at a mean follow-up time of 7.9 years after the onset of symptoms. Recurrence of symptomatic and documented sustained monomorphic ventricular tachycardia occurred in eight patients and could not be predicted by results of long-term ECG monitoring, treadmill exercise testing or programmed stimulation. In conclusion, despite recurrence of ventricular tachycardia, patients with arrhythmogenic right ventricular dysplasia have a favorable outcome when treated medically. Noninvasive studies (imaging techniques, ambulatory ECG monitoring and exercise testing) provide data that may be sufficient in diagnosing arrhythmogenic right ventricular dysplasia.

Adult↗
PubMed1989

Hot-film anemometry for measuring lateral line stimuli.

A hot-film anemometer system has been calibrated and evaluated for the measurement of sinusoidal water motions used in stimulating the mechanosensory lateral line system of a teleost fish. The response of the anemometer system to water motions created by a vibrating sphere was measured over a wide range of frequencies, intensities, and distances from the sphere. The amplitude response of the system to signals along the axis of sphere vibration was found to be linear over a 50-dB range for frequencies from 10-200 Hz, with the lowest end of the dynamic range (between 10(-8) and 10(-9) m) corresponding to physiological measures of best sensitivity in the lateral line system of the mottled sculpin, Cottus bairdi. The measured attenuation of the signal with distance was also linear over this frequency range out to distances of six times the radius ( = 3 mm) of the sphere and followed the predicted falloff rate for a dipolar source. The linear response of the anemometer system over a wide dynamic range encompassing the detection range of the lateral line system, and the match between predicted and measured motions at varying distances from a dipolar source, indicates that hot-film anemometry is a useful technique for measuring low-level, low-frequency signals likely to stimulate the lateral line system and other hydrodynamic detectors.

Animals↗
PubMed1988

Recombinant human interferon-alpha induced cytoreduction in chronic myelogenous leukemia. Results of a multicenter study.

Fourteen patients with Ph'-chromosome positive chronic myelogenous leukemia (CML) in first chronic phase were treated with recombinant interferon-alpha 2c. Interferon-alpha 2c 5 to 10 X 10(6) units s.c. was given for 12 weeks as an induction therapy. Maintenance treatment consisted of interferon-alpha 2c 5 X 10(6) units twice weekly s.c.. Two patients (14%) attained a complete clinical remission and 6 (43%) a partial remission, 3 of whom developed progressive disease during maintenance therapy. A complete disappearance of Ph'-chromosome was achieved in 1 patient. All patients had a more than 45% initial decline of the leukocyte count. Four out of ten patients with an initially enlarged spleen demonstrated reduction in spleen size. Influenza-like symptoms, anorexia, nausea, weight loss and fatigue were common side effects. Interferon-alpha is active in CML but additional clinical investigations are warranted to assess more precisely the therapeutic value of the interferons in this disease.

Clinical Trials as Topic↗
PubMed1987

Successful long-term catheter drainage in an immunocompromised patient with purulent pericarditis.

A case of extensive staphylococcal pericarditis following renal transplantation is described. Purulent pericarditis resolved after 18 days of continuous catheter drainage from the pericardium combined with antibiotic therapy. This case illustrates that life-threatening purulent staphylococcal pericarditis after renal transplantation in an immunocompromised patient may respond to medical therapy.

Anti-Bacterial Agents↗
PubMed1987

Randomized prospective study of ceftazidime versus ceftazidime plus cephalothin in empiric treatment of febrile episodes in severely neutropenic patients.

In a prospective randomized study, ceftazidime monotherapy was compared with a combination of ceftazidime plus cephalothin in 102 febrile neutropenic patients. Thirty bacteriologically documented infections, of which 23 were bacteremias, in 48 clinically assessable patients were treated with ceftazidime alone. Twenty-four bacteriologically proven infections, of which 18 were bacteremias, in 42 clinically assessable patients were treated with a combination of ceftazidime and cephalothin. The clinical response rates in assessable patients were 77% for ceftazidime monotherapy and 88% for the combination. The bacteriological clearance rate was 70% for ceftazidime monotherapy and 79% for the combination. Efficacy against gram-negative pathogens appeared to be excellent, with 93% clearance for ceftazidime monotherapy and 100% clearance for the combination. The bacteriological clearance of gram-positive infections was only 60% for both regimens, with failures mainly due to Streptococcus faecalis and Streptococcus sanguis, which are primarily resistant to both ceftazidime and cephalothin. After addition of vancomycin to those infections which did not respond to empiric therapy, bacteriological clearance rates of 94% (ceftazidime plus vancomycin) and 90% (ceftazidime and cephalothin plus vancomycin) were achieved. Three superinfections were registered in the ceftazidime group and two were seen in the combination group. Other adverse effects of ceftazidime were minimal and were not enhanced by combination with cephalothin. It is concluded that ceftazidime is an effective drug for the empiric treatment of febrile neutropenic patients, especially if one is prepared to modify therapy if resistant gram-positive strains or mycotic infections are encountered. Neither the clinical nor bacteriological cure rates could be substantially improved by adding cephalothin to ceftazidime in initial empiric treatment of febrile neutropenic patients.

Adolescent↗
PubMed1987

Anatomy and differential growth of the lateral line system of the mottled sculpin, Cottus bairdi (Scorpaeniformes: Cottidae).

Scanning electron microscopy and standard histological techniques were used to describe the basic anatomy and postembryonic growth of the lateral line system of Cottus bairdi. The gross anatomy and distribution of lateral line neuromasts in canals and superficially on the skin are similar to what has been reported for many primitive actinopterygian fishes. Both canal and superficial neuromasts showed postembryonic growth in the number of hair cells and size of neuromasts, but canal neuromasts grew more elongate whereas superficial neuromast grew symmetrically. Neuromasts in the mandibular canal grew significantly faster than any other neuromasts and superficial neuromasts on the head showed the least amount of growth. Differential growth of the sculpin lateral line system may be related to the feeding behavior of the animal and to differences in the ambient levels of water noise to which larval and adult fish are exposed.

Animals↗
PubMed1987

Influence of left ventricular function on changes in plasma volume during acetate and bicarbonate dialysis.

The effect of left ventricular function on changes in plasma volume during acetate and bicarbonate dialysis was studied in stable, chronic dialysis patients. Preservation of plasma volume in patients with a normal left ventricular function (mean circumferential fibre shortening velocity (VcF) greater than or equal to 1 circ/s) was significantly less during the first hour of acetate dialysis than during bicarbonate dialysis. However, in patients with impaired left ventricular function (VcF less than 1 circ/s) the decrease in plasma volume was more pronounced during acetate when compared to bicarbonate dialysis. This resulted in a decreased ultrafiltration volume and haemodynamic instability in these patients during acetate dialysis. The fibre shortening velocity increased during acetate and bicarbonate dialysis in patients with a normal left ventricular function, whereas in patients with impaired left ventricular function fibre shortening velocity increased only during bicarbonate dialysis. In conclusion, in patients with an impaired left ventricular function, bicarbonate is preferable to acetate in chronic dialysis.

Acetates↗
PubMed1987

Origin of T-lymphocytes in human mixed hematopoietic colonies.

The presence of T-lymphocytes in mixed hematopoietic colonies (CFU-MIX) has been reported by some investigators. Though depletion before culturing was performed, residual T cells might be responsible for the observed phenomenon. Using nondepleted marrow or bone marrow depleted to about 2%, T-lymphocytes could be detected in mixed colonies. However, reduction of the T-lymphocytes to less than 0.7% by using a modified E-rosette technique or a cocktail of anti-T-cell monoclonal antibodies (WT1, WT32, WT82) in the presence of baby rabbit complement, resulted in mixed colonies free of T-lymphocytes. After addition of 1.75% T-lymphocytes to this T-cell-depleted bone marrow, T-lymphocytes could be detected in most mixed colonies, but not after the addition of the same percentage of irradiated T-lymphocytes. The presence of T cells in mixed colonies was determined by an adapted immunofluorescence technique (WT32 plus GAM-FITC). The results indicate that mononuclear cells with T-lymphocyte antigens are not the offspring of mixed hematopoietic colony-forming progenitors, but of a low number of T-lymphocytes contaminating the bone marrow after insufficient T-cell depletion.

Cytological Techniques↗