Constrictive effect of pancuronium on capacitance vessels

The effects of pancuronium 0.08 mg kg-1, metocurine 0.4 mg kg-1 and tubocurarine 0.4 mg kg-1 on vascular tone were studied in 26 patients undergoing open heart surgery during total cardiopulmonary bypass. With a fixed rate of perfusion, arterial pressure is related directly to total peripheral resistance, while the volume of blood remaining in the extracorporeal reservoir is related inversely to vascular capacity, which depends primarily on venous tone. Pancuronium increased the reservoir volume (average of 780 +/- SEM 250 ml (P less than 0.01). We conclude that under certain circumstances pancuronium constricts capacitance vessels in man.

Biochemical profiles of prostatic fluid from normal and diseased prostate glands

The attempt to identify changes in the biochemical composition of prostatic fluid that might accompany and characterize disease states in the prostate was stimulated by two assumptions based on observations. First, the composition of prostatic fluid was judged to be likely to reflect the metabolic status of at least the epithelial cells accurately. Secondly, the metabolic changes preceding or associated with the development of carcinoma in the prostate seemed likely to be diffuse rather than limited to the histologically abnormal prostatic cells. As a consequence of these assumptions, prostatic fluid obtained from the urethra by digital massage of the prostate was evaluated microscopically and subjected to numerous analytical procedures. Differences in lactate dehydrogenase (LDH) isoenzymes, complement C3, and transferrin concentrations in the prostatic fluid of men with histologically identified carcinoma (Ca) and benign prostatic hyperplasia (BPH) have been observed. The ratio of LDH-5/ LDH-1 was found to have a mean value of 5.94 +/- 0.25(S.E.) in 98 determinations on 83 patients with Ca, and 1.84 +/- 0.14 in 212 determinations on 142 patients with BPH with 10 or less white blood cells per high power field (WBC/hpf) on microscopic examination of the prostatic fluid. Fluid from 52 patients with BPH with greater than 10 WBC/hpf (84 determinations) had a mean ratio of 5.85 +/- 0.88 and from 286 patients with greater than 10 WBC/hpf without an established histologic diagnosis (460 determinations) of 3.12 +/- 0.21. Two hundred twenty-two men under 45 years of age (255 determinations) judged to have a normal prostate clinically had a mean ratio of 0.67 +/- 0.05. The mean transferrin concentration in 44 patients (51 determinations) with Ca was 47.03 +/- 3.76mg/100 ml, in 59 patients with BPH (90 determinations) was 12.97 +/- 1.20, in 23 patients with BPH with > 10 WBC/hpf in the prostatic fluid (38 determinations) was 14.93 +/- 2.19, in 87 patients with > 10 WBC/hpf (92 determinations) was 13.42 +/- 1.41, and in 33 patients less than 45 years of age with clinically normal prostates (33 determinations) was 7.45 +/- 1.08. The mean complement C3 concentration in 46 patients with Ca (57 determinations) was 17.48 +/- 1.60, in 58 patients with BPH (85 determinations) was 3.83 +/- 0.55, in 24 patients with BPH with > 10 WBC/hpf (39 determinations) was 5.87 +/- 0.68, in 93 patients with > 10 WBC/hpf (98 determinations) was 4.47 +/- 0.53, and in 34 patients less than 45 years of age (34 determinations) was 2.06 +/- 0.43. The mean ratio of LDH-5/LDH-1 was significantly greater for Ca than BPH with 10 or less WBC/hpf in the prostatic fluid. The mean concentrations of transferrin and complement C3 were significantly greater in Ca than in all other groups studied. No obvious relationship between stage of disease and these findings was observed. These observations support the suggestion that determination of prostatic fluid composition assists in identifying men with a high risk of cancer of the prostate.

Partial inhibition of castration-induced involution in rat prostate by chloroquine. A preliminary observation

The effect of chloroquine phosphate, a membrane stabilizing agent, on castration-induced involution in the prostate was investigated in adult Sprague-Dawley rats. Chloroquine phosphate (75 mg per kg of body weight) was administered daily by gastric tube on 4 consecutive days beginning 1 day before castration. Control rats received water. All animals were sacrificed 7 days after castration and the ventral prostates were analyzed. The chloroquine group had a mean prostatic weight 17 per cent greater than that of the water-fed control group (P less than 0.01) despite a modest loss in body weight. The activity of cathepsin D, a lysosomal enzyme, in the prostate of treated rats was double that measured in control rats. Histologically, prostates from chloroquine treated rats contained more lysosomal particles that were larger than those from control rats. Serum testosterone reached castrate levels in both groups of animals within 24 hr of castration. These results indicate that it is possible to reduce the rate of prostatic regression by chloroquine, although at a small magnitude, probably through the action of membrane stabilization.

Necrotizing fasciitis of genitalia

A review of 12 patients with necrotizing fasciitis of the genitalia is presented. All patients had rapidly progressing cellulitis and necrosis of the fascia caused by a combination of various organisms, most frequently by Escherichia coli. Beta streptococcus, which is generally thought to be the causative organism in these cases, was present in only 4 patients. Management consisted of extensive surgical debridement, urinary and/or fecal diversion, antibiotics, and necessary reconstructive procedures.

Acute and subchronic neuromuscular blocking characteristics of streptomycin: a comparison with neomycin

The characteristics of the neuromuscular block produced by streptomycin in vivo were studied on the sciatic-tibialis anterior nerve-muscle preparation of eight anaesthetized cats. The lungs of the animals were ventilated mechanically and normocarbia was maintained. During acute exposure to streptomycin (within 2 h), ED50 for blockade of the twitch was 56 (SEM +/- 5) mg kg-1 of the base. The characteristics of block were similar to those of neomycin-induced block in some aspects. There was absence of train-of-four fade and tetanic fade, partial sparing of the responses elicited at 10 Hz and 20 Hz, and total sparing of the 50 Hz tetanus, as well as the post-tetanic twitch. In contrast to neomycin-induced neuromuscular block, however, post-tetanic exhaustion was not observed and prolonged exposure to streptomycin (22-28 h) did not change the characteristics of the block. We conclude that, despite their chemical similarities, streptomycin and neomycin block neuromuscular transmission differently.

Autonomic block, cardiovascular depression and histamine release produced by polymyxin B in the cat

The present study quantifies the autonomic block, the cardiovascular depression and the histamine releasing effects of polymyxin B in nine anaesthetized cats. The dose requirements for 50 per cent depression of the mean arterial blood pressure, the bradycardiac response to vagal stimulation, and the contraction of the nictitating membrane elicited by pre-ganglionic and post-ganglionic stimulation of the cervical sympathetic trunk have a narrow range of scatter, being of the order of 6--12 mg.kg-1 of the polymycin B base. The neuromuscular blocking dose (ED50), previously determined and hereby confired, also falls in the same range. Bradycardia and possibly histamine release are also observable. The relatively unremarkable effect of polymyxin B on the heart rate can be attributed to the balance between the vagal, sympathetic and ganglionic blocks, as well as the possible histamine release. All effects are long-lasting. Thus lack of tissue specificity makes it implausible to explain the neuromuscular and the cardiovascular effects of polymyxin B solely by the cholinergic mechanism of action. Ganglionic block and histamine release do not completely explain hypotension induced by polymyxin B. We propose that all biological effects of polymyxin B derive from a common mechanism of action, which may be its antimembrane antibacterial action. We would like to alert anaesthetists to the possiblity that polymyxin B may cause severe multiple organ system depression, in addition to neuromuscular block.

Interaction of neuromuscular blocking effects of neomycin and polymyxin B

Neomycin and polymyxin B produce neuromuscular blocks with distinct features by different mechanisms of action. In eight anesthetized cats the authors studied their interaction by examining the neuromuscular block produced by an equipotent mixture. Values of onset, potency, dose-response relations, duration and reversibility of block, the train-of-four and tetanic responses during block, the frequency-block relationships, and the posttetanic twitch behavior were well approximated by averaging the corresponding values previously reported for each antibiotic. Edrophonium, 0.2 mg/kg, reversed the block by 8 to 35 per cent. 4-Aminopyridine, 0.6 mg/kg, completely reversed the block and caused a long-lasting overshoot of the twitch response. The authors conclude that neomycin and polymyxin B are additive in neuromuscular effects, not only in terms of potency and duration, but also in terms of the characteristics of the blocks produced.

Analysis of specific proteins in prostatic fluid for detecting prostatic malignancy

In an attempt to identify an indicator(s) specifically associated with prostatic cancer prostatic fluid was collected by rectal massage from patients with prostatic cancer, prostatitis, benign prostatic hyperplasia and from those without recognized prostatic lesions in order to measure various immunoproteins. The proteins examined were IgG, IgA, IgM, complements C3 and C4, and transferrin. Prostatic fluid samples were subjected first to immunoelectrophoresis. Distinct differences in C3, C4 and transferrin concentrations were noted between patients with prostatic cancer and other patients. These proteins were stained heavily in the electrophoresis gels of fluid from cancer patients but were either missing or lightly stained in all other groups. These qualitative determinations were replaced subsequently by a quantitative measurement using the radial immunodiffusion technique. Results of the latter study confirmed the aforementioned observations and indicated that the levels of C3, C4 and transferrin in the prostatic fluid of cancer patients were elevated significantly when compared to all other patient groups. These observations indicate that the measurement of complements C3 and C4, and transferrin in the prostatic fluid may assist in the identification of patients with a high risk of prostatic cancer.

Furosemide in hyaline membrane disease

In a randomized clinical trial designed to evaluate the effect of diuresis on infants with hyaline membrane disease, seven infants were treated with furosemide (2 mg/kg intravenously) and five received 5% dextrose water in 0.225% sodium chloride (control group). Arterial blood gas analyses performed before and during the six hours after treatment showed no significant difference between control and treated infants. Urine output and urine sodium and calcium loss were significantly increased (P less than .05) in the infants receiving furosemide. The diuresis seemed to have no effect on left atrial size determined echocardiographically, whereas measurements of dynamic skinfold thickness suggested mobilization of subcutaneous water. One infant became seriously dehydrated and hypotensive secondary to a massive diuresis. We concluded that furosemide had a potent diuretic effect in infants with hyaline membrane disease but does not improve cardiorespiratory function acutely. This may be because of failure to mobilize pulmonary interstitial fluid in the time period tested. It may also be possible that the presence of pulmonary interstitial fluid does not play an important role in the impairment of gas exchange in the acute stage of hyaline membrane disease.

Antagonism of polymyxin B-induced neuromuscular and cardiovascular depression by 4-aminopyridine in the anesthetized cat

In an attempt to find a better antidote to polymyxin B-induced neuromuscular blockade, the authors tested 4-aminopyridine, 0.4--1 mg/kg, in ten anesthetized cats. The sciatic--tibialis anterior nerve--muscle preparation was used. The neuromuscular blockade was successfully reversed in all cats. Rapidity of reversal depended on the dose of 4-aminopyridine administered. At 0.6--1 mg/kg, reversal of the twitch response from 20 per cent of control to 80 per cent of control required 2.4 (SE, 0.5) min; to 100 per cent, 14.4 (SE, 3.7) min. An overshoot of the recovery of neuromuscular blockade of 6--10 hours' duration followed the reversal. The mechanical twitch response reached a peak of approximately 140 per cent of control at 2 hours. At a lower dosage, 0.4 mg/kg, two of three cats took more than an hour for complete recovery of the twitch response, and the overshoot was approximately 10 per cent of control. The hypotensive effect of polymyxin B was partially reversed, but the bradycardia was not. It is concluded that 4-aminopyridine is an effective antidote to polymyxin B-induced neuromuscular blockade in the cat.

Neuromuscular refractoriness during blockage of transmission. A quantitative study

The effects of suxamethonium and tubocurarine on the refractoriness of neuromuscular transmission were studied in 21 anaesthetized adult subjects under various levels of neuromuscular block. The ulnar nerve was stimulated every 12 s with twin supramaximal stimuli 4 ms apart. At any level of block, the refractory fraction (the fractional decrement of the compound electromyographic response of the adductor pollicis to the second twin stimulus, relative to the response to the first) was used to quantify neuromuscular refractoriness. The magnitude of block was determined by the response to the first stimulus. Correlation between refractoriness and the degree of block was sought. Without block, neuromuscular transmission averaged 23% (SEM 4) refractory with this twin interval. The refractory fraction was increased markedly by suxamethonium, reaching 0.69 (SEM 0.1) at 50% block. Complete refractoriness occurred during 25--75% block in eight of 11 instances. Tubocurarine did not significantly alter refractoriness, paired responses to the twin stimuli decreasing proportionately during block.

Elevated rate of 3H-uridine incorporation in regressing rat ventral prostate

Ventral prostates from adult Sprague-Dawley rats were removed at intervals during the first 2 weeks postcastration. Incubation of tissue with 3H-uridine and 3H-leucine was performed to determine the incorporation rate of radioactivity into the RNA and protein fractions respectively. Prostatic wet weight and 3H-leucine incorporation rate into prostate protein diminished postcastration, whereas 3H-uridine incorporation rate remained relatively high. The data suggest that RNA synthesis is relatively active in comparison with other parameters during regression.

Neuromuscular and cardiovascular depression produced by prolonged exposure to Polymyxin B

It has been reported previously that in cats pre-treatment for 24 to 48 hours with neomycin sulphate resulted in a change in the pattern of neuromuscular block subsequently produced with this antibiotic. The unique characteristics of neomycin-induced neuromuscular block observed during acute exposure gave way to a pattern of block usually observed with tubocurarine. In a similar experiment on six cats we have demonstrated that with polymyxin B prolonged exposure did not result in a comparable time-dependent change in the nature of the neuromuscular block it produced, in terms of train-of-four, tetanic, and post-tetanic behaviour of the neurally-elicited muscle response. The differing characteristics of neuromuscular block seen with various antibiotics, e.g. the aminoglycoside neomycin as opposed to the polypeptide polymyxin B, during acute and sub-chronic exposure is stressed. Previously observed ability of 4 aminopyridine 0.6 mg/kg to reverse the neuromuscular and cardiovascular depression during acute exposure to polymyxin B persisted in prolonged exposure.

Partial inhibition of castration induced ventral prostate regression with actinomycin D and cycloheximide

Sprague Dawley male rats were injected subcutaneously with either actinomycin D or cycloheximide in saline immediately after castration. Control animals received saline only. Treatment was repeated daily for 4 subsequent days, and 24 hr after the last injection rats were sacrificed by decapitation. Ventral prostates were dissected and weighed. Actinomycin D and cycloheximide administration significantly reduced the rate of prostatic weight loss in castrated rats; serum testosterone levels in the control and drug treated animals were comparable. Histologic studies of the prostates indicated that drug treated animals had more active epithelial cells than saline injected controls. These results indicate that the rate of prostatic regression induced by castration can be modified by drugs such as actinomycin D and cycloheximide.