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Biomedical subjects

D W Lee

Publications and source records attributed to D W Lee.

At least 163 records · Page 9Linked to original sources
PubMed1988

Glycosylated and nonglycosylated prolactin in serum during pregnancy.

To study the pattern of release of glycosylated (G-PRL) and nonglycosylated (PRL) under various physiological conditions, we studied normal women from the first trimester of pregnancy through the postpartum period. Immunoreactive PRL variants were immunoprecipitated from 100-microL aliquots of serum, and the precipitates were subjected to gel electrophoresis in the presence of sodium dodecyl sulfate, electrotransferred to nitrocellulose paper, immunoblotted with anti-PRL serum and [125I]protein-A, and autoradiographed. The relative concentrations of the two forms of PRL were indicated by the intensity of the electrophoretic bands. Before pregnancy, serum G-PRL was the predominant PRL form. As pregnancy progressed, increasing amounts of PRL, compared to G-PRL, appeared in the serum, and it reached a maximum by the third trimester. G-PRL was found at all stages of pregnancy, even when the amount of PRL was greatest. After parturition in nonnursing mothers the PRL band again decreased; however, in nursing mothers the PRL band remained prominent. We conclude that the G-PRL and PRL variants may fulfill different physiological roles and, under certain conditions, such as pregnancy and lactation, more of the nonglycosylated PRL may be produced to fill special requirements.

Adult↗
PubMed1987

Effects of centrifugal rotation on analgesia and conditioned flavor aversions.

In the first experiment, 48 female Wistar rats were water deprived and given three conditioning days with saccharin-flavored water (1.5 g/liter) followed by 0, 5, 10 or 15 min of centrifugal rotation (150 rpm). Analgesia was measured by the tail flick test immediately after rotation. Over conditioning days, taste aversions developed. In general, taste aversion strength increased with duration of rotation. Analgesia also was in proportion to duration of rotation; however, over days tolerance developed in all rotated groups. In the second experiment 12 female Wistar rats were water deprived and given naloxone (20 mg/kg) or saline prior to 15 min of rotation. Rotation-induced analgesia was not affected by naloxone. It was concluded that somatic and gastrointestinal reactions to rotation are not served by a single mechanism.

Animals↗
PubMed1987

Adjuvant treatment of operable stomach cancer with polyadenylic.polyuridylic acid in addition to chemotherapeutic agents. Differential effect on natural killer cell and antibody-dependent cellular cytotoxicity.

Peripheral blood lymphocytes of operable stomach cancer patients were evaluated sequentially for their natural killer (NK) and antibody-dependent cellular cytotoxicity (ADCC) activities before and after chemotherapy in association with polyadenylic.polyuridylic acid [poly(A).poly(U)]. Their cytotoxicity was measured by 4 h-chromium release assays, using human K562 and sensitized murine L1210 cells as targets for assays of NK and ADCC respectively. The mean NK cytotoxicity of 89 patients before treatment was significantly lower than that of the 18 sex- and age-matched healthy controls, whereas assays of ADCC showed similar levels of cytotoxicity in both groups. Patients who had received postoperative chemotherapy (5 fluorouracil, 12 mg/kg and adriamycin, 40 mg/M2) once, had, 5 days after injection, NK cytotoxicity levels similar to those before treatment. For these patients, an additional administration of poly(A).poly(U) (100 mg) resulted, 2 days later, in a significant increase in the levels of NK cytotoxicity without affecting the levels of ADCC. Repeated injections of poly(A).poly(U) alternated with chemotherapy induced, consistently, exclusive enhancement of NK activity after each injection. These results suggest that the effector cells for NK and ADCC activities are of functionally different cell populations.

Adult↗
PubMed1987

Glycosylated prolactin is a major circulating variant in human serum.

To determine whether glycosylated human PRL (G-hPRL) is a circulating form of hPRL, serum samples obtained from normal men and women were studied. The PRL was immunoprecipitated from 100-microL aliquots of serum, and the precipitates were subjected to gel electrophoresis in the presence of sodium dodecyl sulfate, electrotransferred to nitrocellulose paper, immunoblotted with anti-hPRL serum and [125I]protein-A, and autoradiographed. The autoradiographs showed an intensely stained G-hPRL band, with a mol wt of 25K, in almost all samples studied. The nonglycosylated PRL (hPRL) band, with a mol wt of 23K, was much more variable in staining intensity from individual to individual. Some samples also had a 27K glycosylated immunoreactive PRL band. Serum samples were also obtained every other day from two women throughout a 28-day period; again, each sample had an intensely stained G-hPRL band and a hPRL band that varied in staining intensity from day to day. In contrast, however, to the G-hPRL/hPRL pattern in serum samples obtained from normal women and men, samples from pregnant women at the onset of spontaneous labor showed opposite results, that is an intensely stained hPRL band but only a faintly stained G-hPRL band. These results indicate that G-hPRL is an important component of circulating PRL in normal men and women and that it may vary in amount in certain physiologic states.

Adolescent↗
PubMed1986

Demonstration of 20K growth hormone in human plasma by gel electrophoretic-immunostaining-autoradiographic assay (GEISAA).

A variant of human growth hormone (hGH), in which 15 amino acids are missing (commonly referred to as 20K-hGH in contrast to the traditional form which is referred to as 22K-hGH), is known to exist in human pituitary glands. However, lack of a method to measure it in blood has hindered investigations of its physiopathology. We have applied a newly-developed technique called GEISAA for its detection in small volumes of human plasma. The method is based upon the lower Mr of the variant and its ability to partially crossreact with existing antibodies for 22K-hGH. It consists of retrieval of the substance from plasma by immunoprecipitation, separation from 22K-hGH by NaDodSO4-polyacrylamide gel electrophoresis, transfer onto nitrocellulose paper by electroblotting and visualization by immunostaining and autoradiography. It revealed the 20K-hGH in plasma of some normal individuals and in that of an acromegalic patient. Furthermore, plasma concentration of the variant rose in conjunction with 22K-hGH following exercise, a natural stimulus for GH release. These results show that the 20K-hGH circulates under normal conditions and it is measurable by GEISAA using existing antibodies.

Adult↗
PubMed1986

The effect of diet on bile acid kinetics and biliary lipid secretion in gallstone patients treated with ursodeoxycholic acid.

Effects of specific dietary alterations in patients with radiolucent gallstones treated with ursodeoxycholic acid (UDCA, 750 mg at bedtime) were investigated. Patients were allocated randomly to one of four diets: standard (500 mg cholesterol/day), low-cholesterol (250 mg/day), added-bran (30 g/day), or substituted medium-chain triglycerides (MCT) oil (20% of fat). Dietary intake and good compliance were verified by computerized analysis of dietary diaries. Bile-acid kinetics (26 patients) or secretion of biliary lipids (23 other patients) were determined at enrollment and at 6 and 9 mo, respectively, during treatment. Although MCT further decreased the UDCA-induced decrease in the synthesis of chenodeoxycholic acid, it did not lessen desaturation of bile. Otherwise, compared to the standard diet, no experimental diet significantly altered the UDCA-induced increase of the pools of total bile acids and UDCA or the UDCA-induced decrease in synthesis of bile acids and in biliary secretion or saturation of cholesterol. If these dietary manipulations facilitate dissolution of gallstones by UDCA, they do so by other mechanisms.

Adult↗
PubMed1986

Release of the 22,000- and the 20,000-dalton variants of growth hormone in vivo and in vitro by human anterior pituitary cells.

Using a combination of polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and immunoblotting with antihuman GH (anti-hGH) serum, we quantitatively and independently measured the major 22,000-dalton form of hGH (hGH22K) and the 20,000-dalton form (hGH20K). This technique was equally effective in assaying cell culture media or human sera. We studied isolated human pituitary cell cultures during a 16-day incubation period with and without stimulation by GH-releasing hormone (GHRH). Under basal conditions, the cells released 2.83 +/- 0.24 (+/- SEM) microgram hGH22K/ml . day and 0.67 +/- 0.17 microgram hGH20K/ml . day. GHRH (10(-8) M) treatment resulted in stimulation of both hGH22K and hGH20K by 24 h. We also measured both hGH22K and hGH20K in the sera of normal subjects before and after an iv bolus injection of 100 micrograms GHRH. hGH20K increased as did hGH22K. Peak concentrations of both variants occurred 45 min after GHRH administration. The results of this study indicate that the combination of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting is an accurate and effective means of separately assaying hGH22K and hGH20K. We also demonstrated that primary monolayer cultures of human pituitary cells are an excellent model system for study of the secretion of these two hGH variants.

Adult↗
PubMed1986

Synthesis and release of glycosylated prolactin by human decidua in vitro.

To determine whether human decidual tissue synthesizes and secretes a glycosylated form of PRL (G-hPRL), explants of decidua obtained after normal term delivery were cultured for up to 5 days. During each day of incubation, the decidual explants incorporated [3H]mannose and [3H]glucosamine into immunoprecipitable G-hPRL. The explants released 33-50% less G-hPRL than hPRL. The release of decidual G-hPRL was unaffected by treatment with TRH (10(-4)-10(-8) M) or dopamine (10(-5)-10(-9) M) during a 4-h incubation period. G-hPRL also was sought in samples of amniotic fluid. Glycosylated hPRL was detected in all amniotic fluid samples from normal pregnant women at 32-40 weeks of gestation. These results indicate that human decidual explants in vitro may be used as a model system to study the secretion of G-hPRL and its regulation during pregnancy.

Amniotic Fluid↗
PubMed1985

Effect of dietary cholesterol on biliary lipids in patients with gallstones and normal subjects.

The purpose of this study was to determine the effect of dietary cholesterol on biliary lipids in subjects with and without gallstones. Twelve patients with asymptomatic gallstones (six men, six women) were assigned diets containing 500, 750, and 1000 mg cholesterol daily for 3-wk periods in random sequence. Seven healthy women similarly were assigned diets containing 500 and 1000 mg cholesterol daily. With increasing dietary cholesterol in patients with gallstones, biliary saturation indices and molar percents of cholesterol and phospholipids increased significantly while molar percent of biliary bile acids decreased significantly. With increasing dietary cholesterol in healthy women, the biliary saturation index and molar percent of cholesterol increased significantly; the mean saturation index exceeded unity on the diet containing 1000 mg cholesterol daily. In conclusion, augmented dietary cholesterol for brief periods increased biliary cholesterol saturation in subjects with and without gallstones.

Bile↗
PubMed1985

Cleaved prolactin: evidence for its occurrence in human pituitary gland and plasma.

A form of PRL that is cleaved in its large disulfide loop has been reported in rat and mouse pituitary glands, but it is not known whether it exists in the human pituitary gland and whether it circulates in blood. Recently, we developed an immunoelectrophoretic technique which is capable of measuring immunoreactive variants of PRL and other hormones in plasma. We describe here detection of cleaved PRL in normal and tumor pituitary tissue from a prolactinoma patient and in the plasma of pregnant women.

Autoradiography↗
PubMed1985

Dynamic approach in the diagnosis of thoracic outlet syndrome using somatosensory evoked responses.

The clinical diagnosis of thoracic outlet syndrome (TOS) is controversial. Objective documentation of this disorder is often unobtainable, even with electrodiagnostic techniques. This preliminary report describes an objective diagnostic method of evaluating TOS using somatosensory evoked potential testing (SEP) and dynamic arm positioning. Evoked potentials were recorded over the brachial plexus (N9) and C7 cervical vertebra (N13) after distal stimulation of the median and/or ulnar nerves. This was performed with the arm both at the side (anatomic position), and then positioned in abduction and external rotation. Absolute and interpeak latencies were measured in both positions. Of 14 patients clinically suspected of having TOS, six showed normal N13 evoked responses in the anatomic position despite a disappearance of this potential when tested with the symptomatic arm in the dynamic position of abduction and external rotation. Fourteen control subjects had normal responses with the arm tested in both positions. The SEP coupled with the dynamic stress of the nerves coursing through the thoracic outlet may be helpful as a new objective aid in the diagnosis of TOS.

Adult↗
PubMed1984

Detection of a high molecular weight variant of prolactin in human plasma by a combination of electrophoretic and immunologic techniques.

We have developed a method for detecting in human plasma a form of prolactin (PRL) with an apparent molecular weight (MW) of approximately 25,000, distinct from traditional human PRL (hPRL) which has a MW of 23,000. The method is based upon the higher MW of the variant and its ability to partially cross-react with antibody to 23K hPRL. It consists of retrieval of the protein from plasma by immunoprecipitation, its separation from 23K hPRL by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transfer onto nitrocellulose paper by electroblotting, followed by detection with immunostaining and autoradiography. The method is sensitive enough to detect hPRL and its 25K variant in 100 microliter of human plasma. All plasma tested so far has shown the presence of the new form. The method has also revealed another protein in human plasma that cross-reacts with a specific antibody to 23K hPRL. This protein may constitute an additional post-translational variant of hPRL. The 25K variant reported here most likely represents the glycosylated form of the hormone recently detected in ovine and human pituitary glands. The method described can be adapted to detect other plasma components for which an antibody is available.

Autoradiography↗