Biomedical subjects
Publications and source records attributed to P Iversen.
Magnetic resonance imaging offers new possibilities in investigation of the prostate gland. Current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be useful in the staging of carcinoma of the prostate.
Tissue characterization for separating malignant from benign tissue is a clinically very important potential of magnetic resonance imaging (MRI). In this study quantitative determination of T1- and T2-relaxation processes was accomplished in five healthy volunteers, 10 patients with benign hyperplasia of the prostate gland and eight patients with prostatic carcinoma. Histological verification was obtained in all the patients. The measurements were performed on a wholebody MR-scanner operating at 1.5 T using six inversion recovery sequences (TR = 4000 msec) for T1-determination and a 32 spin-echo sequence (TR = 3000 or 2000 msec) for T2-estimation. The T1-relaxation curves all appeared monoexponential, whereas the T2-curves in most cases showed a multiexponential behaviour. A considerable overlap of the relaxation curves was seen. Consequently, we found no statistically significant differences between the T1- or the T2-relaxation times of the three groups investigated. It is concluded that tissue characterization based on relaxation time measurements with MRI does not seem to have a clinically useful role in prostatic disease.
A new system for patient fixation in radiation treatment is described. The system consists of an airtight plastic bag with a contents of polysterol microspheres. A valve allows evacuation which results in a rigid close fitting cast. The system was compared with conventional foam cast fixation in 29 patients who were treated for carcinoma of the breast. The patients received radiation treatment over 22 fractions, and portal X-ray pictures were obtained at every second treatment. The portal films were compared with the stimulator radiographs and the variation in the position of the centre cross were measured in cranio-caudal and transversal direction as well as the rotation of the centre cross. The results showed that the daily reproducibility of the patient set-up was considerably improved by the new system, the centre cross deviation of the position of the actual radiation field to the centre cross of the intended field being less than 1 mm in 50% of the cases. The system is time-saving and cheap compared to conventional fixation systems.
Between 1979 and 1984 the Copenhagen Renal Cancer Study Group randomized 72 patients nephrectomized for stages II and III renal adenocarcinoma in a prospective study of postoperative radiotherapy versus observation. Radiotherapy was 50 Gy in 20 fractions to the kidney bed, ipsi- and contralateral lymph nodes. 7/72 were excluded from further analysis because of major protocol violations. 33/65 were in stage II, 32/65 in stage III. Relapse was found in 31/65 = 48% during the follow-up period without any difference between the two groups. 12/27 = 44% had significant complications from stomach, duodenum or liver, median 5 mo., range 1-44 mo. after radiotherapy. In 5/27 = 19% did the postirradiatory complications contribute to the death of the patients. Patients with stage II tumours survived significantly better than those with stage III tumours (p less than 0.05), but no significant differences in survival could be demonstrated between patients randomized to postoperative radiotherapy or observation. It is concluded that postoperative radiotherapy as given in the present study is without any beneficial effect on relapse rate and survival. Moreover, the treatment is associated with an unacceptable complication rate.
Magnetic resonance imaging offers new possibilities in the investigation of the prostate. The current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be of value in the staging of carcinoma of the prostate.
Among 84 patients with prostatism selected for transurethral resection of the prostate, 18 had a maximum flow at spontaneous uroflowmetry less than or equal to 7 ml/sec. Preoperatively there was no significant difference between patients with maximum flow less than or equal to 7 ml/sec (Group 1) and patients with maximum flow greater than 7 ml/sec (Group 2) in age, duration of symptoms, symptom scores, bladder volume, residual urine, and detrusor pressure at maximum flow. Patients in Group 1, however, had significantly lower urethral resistance and bladder volume independent maximum flow than patients in Group 2. Postoperatively, patients with preoperative maximum flow less than or equal to 7 ml/sec improved significantly in symptom scores and urodynamic findings apart from bladder volume and detrusor pressure at maximum flow. There were no significant differences between groups in postoperative symptom scores or urodynamic findings. We conclude that preoperative maximum flow rates less than or equal to 7 ml/sec at spontaneous uroflowmetry were related to high urethral resistance and not detrusor decompensation among patients with prostatism, and that patients with maximum flow rates less than or equal to 7 ml/sec fared as well postoperatively as patients with maximum flow greater than 7 ml/sec.
In an attempt to identify preoperatively patients who will not benefit from prostatectomy, 84 patients with prostatism about to undergo transurethral resection of the prostate were evaluated prospectively with preoperative and postoperative symptom analysis and urodynamic examination, including cystometrograms. Of the patients 67 were followed at 3 months and 54 again at 12 months. Preoperatively, 65 per cent of the patients had uninhibited detrusor contractions, while 38 had persistent postoperative uninhibited detrusor contractions at 3 months. Patients in whom uninhibited detrusor contractions persisted postoperatively more often had unacceptable postoperative symptoms. Of the patients 13 per cent believed the symptoms to be the same or worse at 3 and 12 months. The incidence of uninhibited detrusor contractions in these patients was 57 and 71 per cent, respectively. While this finding suggests that persistent postoperative uninhibited detrusor contractions are associated with an unfavorable surgical outcome, we could not predict which patients would have uninhibited detrusor contractions following prostatectomy by use of preoperative cystometric findings together with detailed symptom analysis. Thus, we failed to define a role for preoperative cystometric screening of patients with prostatism.
Uroflowmetry is a valuable urodynamic screening procedure in selecting patients with prostatism for surgery. A prospective study was undertaken in which patients were selected for transurethral resection of the prostate by means of nonurodynamic data only. All patients underwent extensive urodynamic testing. Fifty-three patients were studied preoperatively, while 38 were examined at three months and 22 at twelve months postoperatively. A weak correlation was noted between maximum flow rate and symptom scores, pressure variables, and minimum urethral resistance. However, classification of patients by groups of high, medium, and low maximum flow rates did not identify groups of patients with less favorable outcome of surgery, i.e., patients with higher flow rates did as well as those with lower flow rates. A clear role for spontaneous uroflowmetry could not be identified in the preoperative evaluation of patients with prostatism.
A prospective evaluation was done of 84 patients who were selected for transurethral prostatectomy based on the presenting symptoms and findings at cystoscopy. In addition, urodynamic studies were performed but the results were not made available to the urologist who selected the patients for surgery. Postoperative symptom analysis and repeat urodynamic examinations were done at 3 months in 68 patients and at 12 months in 50. There was no significant association between irritative symptoms and uninhibited detrusor contractions. Furthermore, no associations were identified between obstructive symptoms and infravesical obstruction as defined by urodynamic criteria. The study failed to identify a need for routine invasive urodynamic investigation of patients with benign prostatic hypertrophy.
The renal handling and renal lymph concentrations of tetroxoprim and metioprim, 2 trimethoprim analogs, were investigated during constant intravenous infusion in 8 dogs. The mean ratios of tetroxoprim and metioprim clearance to creatinine clearance were 0.40 and 0.16 respectively. After compensation for protein binding, both antimicrobials were found to undergo a renal tubular net reabsorption of 55 to 60 per cent of the filtered amount. Renal lymph was obtained by direct cannulation of capsular lymphatics, and the mean lymph-to-arterial plasma concentration ratios were 0.93 and 0.74 for tetroxoprim and metioprim, respectively. Renal tissue concentrations of the 2 microbials were many times higher than the simultaneous concentrations in plasma, suggesting that lymph concentrations do not represent the entire interstitial compartment or that significant amounts of antimicrobial are located intracellularly. Tetroxoprim and metioprim concentrated well in the kidney, but their potential use in the treatment of pyelonephritis awaits verification in clinical trials.
The results of the treatment of chronic bacterial prostatitis are disappointing. The current status of antimicrobial and immunological research is described. While both a local and systemic antibody response is demonstrated in acute bacterial prostatis, only a local antibody production is found in chronic bacterial prostatis. This response as reflected in the expressed prostatic secretion is specific for the infecting organism and immunoglobulin A is the major antibody class involved. Drug penetration into the prostate has mainly been studied in dogs and the ideal drug appears to be a lipid-soluble base which will concentrate in the slightly acidic prostatic secretion because of ion-trapping. However, these results are not directly applicable to humans because of the slight alkalinity of human prostatic secretion, the localization of the chronic inflammatory process in the interstitium, and the evidence of an active secretory mechanism for trimethoprim. The clinical consequences of these findings are discussed in relation to several recent studies and the treatment with lipid-soluble bases with a low plasma protein binding over extended periods is recommended.
The influence of a transurethrally inserted 8.3-F modified J-nephrostomy catheter on urinary flow rate was investigated by both spontaneous uroflowmetry and pressure flow study in patients with almost identical bladder volumes. No statistically significant differences were found between maximum and mean flow rates obtained by spontaneous uroflowmetry and pressure flow study, respectively. Consequently, transurethral catheter placement is recommended in routine urodynamics.
We evaluated 46 patients who underwent transurethral resection of the prostate for abdominal straining associated with voiding. All patients were evaluated preoperatively by means of detailed symptom analysis, excretory urography, cystoscopy and urodynamic studies, including spontaneous uroflowmetry, medium fill water cystometry and pressure flow study. Of the patients 72 per cent strained preoperatively and the majority continued to strain 3 and 12 months postoperatively. No correlation was identified between straining and urodynamic or symptomatologic indicators of bladder outlet obstruction. Patients who strained and those who did not strain experienced neither subjective nor objective differences postoperatively. A positive correlation between straining and age was identified. We speculate that straining might be based on individual habits and that the tendency to strain increases with advancing age.
To determine whether the minimum urethral resistance was useful to identify bladder outlet obstruction in prostatectomy candidates, 46 patients undergoing transurethral resection of the prostate were evaluated by means of detailed symptom analysis, cystoscopy, rectal examination and post-void residual urine determination. In addition, each patient underwent extensive urodynamic testing, the results of which were not made available to the operating urologist as patients were selected for surgery. This prospective, blind evaluation has been completed in 33 and 15 patients 3 and 12 months postoperatively, respectively. A correlation is noted between the minimum urethral resistance, and symptomatology and uroflowmetry but no correlation was identified with prostatic length and the resected prostatic weight. The minimum urethral resistance was not useful in predicting which patients would benefit from transurethral resection of the prostate. It is concluded that symptom analysis generally is a better predictor of the outcome of transurethral resection of the prostate than is minimum urethral resistance.
There were 51 patients with prostatism who were selected for transurethral resection of the prostate using clinical nonurodynamic criteria. Urodynamic evaluation revealed that 13 patients had preoperative maximum urine flow rates greater than 15 ml. per second. The favorable postoperative outcome in clinical and urodynamic terms in this group of patients with high preoperative urine flow is discussed.
The importance of nonpharmacologic and pharmacologic interventions in the treatment of alcohol withdrawal is not known. A randomized, double-blind, placebo-controlled trial was conducted with 41 patients in alcohol withdrawal in an emergency department. The patients received either supportive care (10 min of standardized assessments, reassurance, reality orientation, and nursing care an hour) with three doses of sublingual lorazepam 2 mg every 2 hr (21 patients, drug group) or supportive care with three doses of sublingual placebo every 2 hr (20 patients, no-drug group). Immediately before each drug dose, the clinical course of alcohol withdrawal was assessed hourly by the Clinical Institute Withdrawal Assessment for Alcohol (CIWA-A). Interraters reliability in using CIWA-A was high. After each assessment, supportive care was given for 10 min before each dose. After completion of a 7-hr initial phase, patients were discharged and reassessed daily for 5 days. Thirty-seven patients (90.2%) improved in the initial phase. Treatment failures (CIWA-A greater than 10) were more common in the patients treated without drug (3/20, 15%) than in those treated with drug (1/21, 4.8%). Overall variations in intergroup CIWA-A scores during the initial phase were not significant. The rate of improvement of CIWA-A scores over the first 2 hr after drug was slightly faster in patients receiving lorazepam than in the control group. CIWA-A scores were the same during follow-up. These results indicate that most outpatients in mild to moderate alcohol withdrawal without medical complications improve without drug therapy in the emergency department setting.
Constant-infusion experiments were performed in 14 dogs to determine the penetration into bone of rifampin and a new C-3 substituted rifamycin, DL 473. The drugs were assayed in cortical bone and medulla from tibia-femur and cortical and cancellous bone from rib. After identical dosage, the concentrations of DL 473 appeared to be higher, except in the medulla, although the serum concentrations of rifampin were almost twice as high as those for DL 473. The concentrations of both drugs in all bone areas were several times higher than their minimum inhibitory concentrations against pathogenic Staphylococcus aureus.
In addition to routine evaluation, 68 patients with prostatism underwent blinded urodynamic testing prior to transurethral prostatectomy and were reexamined symptomatologically and urodynamically at 3 and 12 months after surgery to determine if prostatic weight could predict postoperative outcome. Resected prostatic weight correlated with estimated weight at cystoscopy and with obstructive symptoms, but not with urodynamic variables of infravesical obstruction. Patients with small prostates improved symptomatologically to the same degree as patients with larger glands, although they did not improve to the same degree urodynamically. Prostatic weight, therefore, could not be used to predict the outcome of transurethral surgery.