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Biomedical subjects

C Lee

Publications and source records attributed to C Lee.

At least 955 records · Page 53Linked to original sources
PubMed1983

Observations on the immunomodulator NPT 15392 in New Zealand Black mice.

NPT 15392, an experimental drug with immunomodulatory activities, was administered to New Zealand Black (NZB) mice over an extended period of time. Anti-erythrocyte antibody levels and spleen weights increased with age in NZB mice, while hematocrits (Hct) declined slightly. In addition, both antierythrocyte antibody and spleen weights were negatively correlated with Hct (-0.545 and -0.848, respectively). NPT 15392 therapy retarded the development of anti-erythrocyte antibody in young mice (11 weeks old), and reduced the levels of this autoantibody in 38 week old animals. The slight improvement in the index of anemia in the older treated mice was also accompanied by a substantially lower spleen weight. No significant effect of NPT 15392 therapy was observed on Hct levels. These results indicate that NPT 15392 has a modifying effect on the evolution of the autoimmune process in this strain of mouse.

Aging↗
PubMed1983

The effect of CIS hydroxyproline on ventral prostatic growth in rats.

Changes in prostatic collagen were measured in Sprague-Dawley rats to gain further insight into the relationship between this stromal component and androgen mediated prostatic growth. Regulation of prostatic collagen by other endocrine factors was also studied. Collagen content per prostate was estimated by determination of tissue levels of hydroxyproline. The 1st experiment examined changes in the content of hydroxyproline in the prostate during pre- and post-pubertal growth with the use of rats between 21 and 80 days of age. As the animals grew, their prostatic weights and hydroxyproline contents increased in a parallel fashion (correlation coefficient R = 0.977, p less than 0.01). In the 2nd experiment, rats were castrated for a period up to 28 days. The hydroxyproline content in the prostate did not change significantly by castration despite a marked decrease in prostatic weights. Results of the 3rd experiment indicated that castration-hypophysectomy or castration-hypophysectomy plus estrogen treatment did not significantly change the content of prostatic hydroxyproline from that in the untreated intact animals. The 4th experiment studied the effect of the collagen synthesis inhibitor, cis-4-hydroxyproline, on prostatic growth. Subcutaneous injection of cis-4-hydroxyproline to castrated testosterone treated rats caused a significantly slower increase in total ventral prostatic weights and contents of protein, DNA and hydroxyproline than those of saline treated controls. This inhibition in prostatic growth is unlikely to be related to any antiandrogenic effect of cis hydroxyproline as the protein/DNA ratio in the prostate was the same for both saline and cis-4-hydroxyproline treated groups. Electron microscopic studies revealed that cis-4-hydroxyproline treatment resulted in a derangement of the basement membrane in the ventral prostate. The above results suggest that collagen plays an important role in limiting prostatic growth since inhibition of collagen synthesis by cis-4-hydroxyproline retarded the testosterone induced increase in prostatic weight, DNA, protein and hydroxyproline content in the prostate of rats.

Animals↗
PubMed1983

Patterns of smoking: measurement and variability in asymptomatic smokers.

Measurements of patterns of puffing (cigarette-holder pneumotachograph) and ventilation (plethysmography) were made in ten asymptomatic smokers during the smoking of a cigarette, on four separate occasions. There were marked individual differences and these were consistent over 3-5 weeks. In itself, the pattern of smoking could be responsible for a threefold variation in smoke intake. Puffing but not inhalation became less intense as a cigarette was smoked. It was not possible to predict indices of absorption from smoking patterns. Certain smoking patterns, e.g. small puff volume, low puff frequency, short duration of inhalation and expulsion of volume between puff and inhalation, may be less harmful than others and this may explain why some individuals remain healthy despite a lifetime of smoking.

Adolescent↗
PubMed1983

Biphasic response of the rat lateral prostate to increasing levels of serum prolactin.

Our previous work has shown that an increase in serum prolactin (Prl) levels produced by two pituitary grafts specifically enhances testosterone-stimulated growth of the rat lateral prostate. Since Prl has been shown in several mammalian systems to have biphasic effects, i.e., stimulatory at low doses and inhibitory or without effect at high levels, the present study was undertaken to determine whether the prostate gland would respond differentially to increasing Prl levels. Adult male rats were castrated, given s.c. testosterone implants and grafted with 0, 1, 2, 4 or 6 pituitaries under the renal capsule. Three weeks later all animals were sacrificed. The three prostate lobes were removed for analysis and blood was collected for Prl and testosterone radioimmunoassay. There were no significant differences in ventral and dorsal lobe parameters among the 5 groups whereas the lateral lobe showed a marked tropic response. As serum Prl levels increased, the weight of the lateral prostate first increased and then diminished. Mean weights (mg +/- SEM) were: 40 +/- 3, 65 +/- 3, 76 +/- 6, 70 +/- 4 and 59 +/- 3 for animals with 0, 1, 2, 4 and 6 grafts, respectively. Protein and DNA levels showed the same response pattern. To ensure that this response was a result of elevated Prl, the study was repeated with daily injections of bromoergocriptine (CB-154). The mean weights after 3 weeks in the control and CB-154-treated animals, respectively were: 0 graft, 44 +/- 3 and 43 +/- 2; 2 grafts, 81 +/- 4 and 41 +/- 3; 6 grafts, 56 +/- 3 and 44 +/- 3. Again, a biphasic response occurred in control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Different definitions of alcoholism, II: A pilot study of 10 definitions in a treatment setting.

The authors have developed the Alcohol Poly-Diagnostic Interview, which permits the operationalization of the 10 leading definitions of alcoholism used in the United States and Europe. In a pilot study of 23 patients in an outpatient alcohol treatment facility, all patients were identified as alcoholic by seven of the diagnostic schemes; the other three diagnostic schemes identified at least 78% of the patients as alcoholic. The authors also found that the Diagnostic Interview Schedule was sensitive to the diagnosis of alcoholism among treated patients. This approach should facilitate further research into the relationship among various definitions of alcoholism and studies of their validity.

Adult↗
PubMed1983

The dural lucent line: characteristic sign of hyperostosing meningioma en plaque.

Hyperostosis of the skull associated with en plaque form of meningioma may present a diagnostic challenge, since the intracranial part of the tumor is not visualized by skull radiography, computed tomography (CT), or other neuroradiologic methods. The authors report four cases of hyperostosing meningioma en plaque demonstrating a characteristic feature: a subdural layer of ossification along the hyperostotic bone with a dural lucent interface. Polytomography or high-resolution CT at bone window settings is necessary to identify the dural lucent line. The absence of this sign does not exclude meningioma en plaque.

Adult↗
PubMed1983

Atracurium during halothane anesthesia in humans.

The neuromuscular effects of atracurium were studied in 20 patients anesthetized with 0.8% end-tidal halothane. Neuromuscular blockade was monitored by recording the electromyographic activity of the adductor pollicis muscle resulting from stimulation of the ulnar nerve. Four groups of five patients received single atracurium doses of 0.1, 0.15, 0.2, or 0.4 mg/kg, respectively. The block produced by 0.1 mg/kg was 25-72% and lasted 6-21 min. The block produced by 0.15 mg/kg was 69-93% and lasted 16-32 min. The blocks produced by 0.2 and 0.4 mg/kg were 95% or greater and lasted 42-84 min and 55-104 min, respectively. When indicated, intubation was easily performed in all patients receiving 0.2 and 0.4 mg/kg. The block could be readily antagonized by neostigmine and atropine. Changes in heart rate and blood pressure following atracurium administration averaged less than 5%.

Adolescent↗
PubMed1983

Modification of atracurium blockade by halothane and by suxamethonium. A review of clinical experience.

The effects of halothane and of prior administration of suxamethonium on atracurium neuromuscular blockade have been investigated. Halothane potentiated the intensity of block produced by atracurium 0.1 or 0.15 mg kg-1. Duration of block was prolonged (27%) by halothane with a small dose of atracurium (0.15 mg kg-1) and was also prolonged (29%) with larger doses of atracurium (0.4 mg kg-1). Prior suxamethonium 1 mg kg-1 increased the intensity of block after atracurium 0.15 mg kg-1 from 52% (control) to 84%, but caused minimal change in duration of atracurium blockade.

Adolescent↗
PubMed1982

A comparison of 3,4-diaminopyridine and 4-aminopyridine in the anaesthetized cat.

3,4-Diaminopyridine and 4-aminopyridine were compared in the anaesthetized cat and found to be equiactive in their anti-curare activity. This in vivo similarity is at variance with previous in vitro studies which demonstrate 3,4-diaminopyridine to be more active than 4-aminopyridine at the neuromuscular junction. Possible reasons for the similarity between the two aminopyridines at the in vivo neuromuscular junction are discussed and it is concluded that 3,4-diaminopyridine has only marginal advantages over 4-aminopyridine as a potential anti-curare agent.

4-Aminopyridine↗
PubMed1982

Alterations of glial tumor cell Ca2+ metabolism and Ca2+-dependent cAMP accumulation by phorbol myristate acetate.

C6 glial tumor cells exposed to phorbol myristate acetate (PMA) possessed lowered cAMP content, reduced ability to accumulate cAMP in response to norepinephrine or cholera toxin, and a 3-fold increase in the concentration of norepinephrine producing 50% of the maximal rate of cAMP accumulation. Detectable effects on cAMP accumulation occurred within 10 min of exposure to PMA, and prominent effects by 2 h. PMA similarly affected cells pretreated with cycloheximide. In contrast, Ca2+-depleted preparations of control and PMA-treated cells accumulated cAMP identically in response to norepinephrine or cholera toxin. Ca2+ restoration, which increased the rate of cAMP accumulation in control cells severalfold, did not enhance cAMP accumulation in PMA-treated cells. Neither high catecholamine nor high extracellular Ca2+ concentrations reversed the suppression of cAMP accumulation by PMA. Trifluoperazine, which inhibited the Ca2+-dependent component of norepinephrine-stimulated cAMP accumulation in control cells, did not significantly reduce norepinephrine-stimulated cAMP accumulation in PMA-treated cells. Cell free preparations of control and PMA-treated cultures did not differ significantly in calmodulin content or in Ca2+-stimulated adenylate cyclase, Ca2+-dependent cAMP phosphodiesterase, and (Ca2+-Mg2+)-ATPase activities. The Ca2+ content, however, of intact cells decreased with time of PMA treatment. Within minutes after exposure to PMA, the ability of Ca2+-depleted cells to take up 45Ca was significantly reduced. Both 45Ca uptake and Ca2+-dependent cAMP accumulation were reduced over the same PMA concentration range.

3',5'-Cyclic-AMP Phosphodiesterases↗