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Biomedical subjects

M Lee

Publications and source records attributed to M Lee.

At least 865 records · Page 48Linked to original sources
PubMed1989

Compensatory adrenal hypertrophy following unilateral adrenalectomy of fetuses of rats given alcohol throughout gestation.

The effect of maternal alcohol consumption on fetal compensatory adrenal hypertrophy following unilateral adrenalectomy was studied in rats. Females were given 20% alcohol in tap water for 4 weeks prior to mating and 30% alcohol in tap water throughout gestation (alcohol), or were pair-fed to the alcohol group (pair-fed) or were fed ad libitum (control). On day 20, fetuses were unilaterally left-adrenalectomized or sham operated. Mothers were sacrificed on day 22 of gestation and right adrenals of adrenalectomized, sham-operated, and unoperated fetuses were removed and weighed. Some adrenals were fixed, sectioned, and stained for histological examination. Adrenalectomized fetuses of all three dietary treatment groups demonstrated compensatory hypertrophy. Adrenals of alcohol-exposed fetuses weighed less than those of pair-fed or control fetuses, and the ratio of adrenal weight/body weight was greater, regardless of surgical procedure. Histological sections of right adrenals of left-adrenalectomized fetuses showed larger cells and widened sinusoids, compared to unoperated fetuses in the corresponding dietary treatment groups. These results are consistent with a retardation in adrenal growth and development as a result of alcohol exposure, but show that alcohol consumption throughout gestation does not affect the ability of the adrenals to undergo compensatory hypertrophy following unilateral adrenalectomy.

Adrenal Glands↗
PubMed1989

Presence of cdc2(+)-like proteins in the preimplantation mouse embryo.

An antibody raised against a portion of the human equivalent of the yeast cdc2+ protein reacts with a 34K protein in mouse cell lines and early embryonic cells. Western blot analysis coupled with phosphatase treatment of material collected from the early preimplantation embryo has shown that the murine cdc2+ homologue does not correspond to the previously described newly synthesised proteins that are phosphorylated in a cell-cycle-dependent fashion [Howlett, 1986]. The cdc2(+)-like protein is converted into a slower migrating form on entry into S-phase and is further modified during G2 prior to mitosis. Studies of embryos that are held in extended periods of M-phase, i.e. unfertilised eggs or 1-cell embryos treated with nocodazole, demonstrate that the cdc2(+)-like protein becomes demodified in these cells.

Amino Acid Sequence↗
PubMed1989

Improving patient comprehension of literature on smoking.

This study was designed to determine if simplification of smoking literature improved patient comprehension. Subjects (N = 129) were randomized in three groups: to receive no smoking booklet, receive one written at the 5th grade, or the 10th grade reading level. Subjects receiving the 5th grade booklet showed 13 percent better comprehension than those receiving the 10th grade booklet, and 18 percent better than the controls. Comprehension of written smoking materials can be improved by adjustment of the reading grade level.

Adult↗
PubMed1989

Effect of maternal alcohol consumption on the fetal thyroid in the rat.

To investigate the effect of maternal alcohol consumption on the development of the fetal thyroid gland, Sprague-Dawley rats were given 20% ethanol for 4 weeks prior to mating and 30% ethanol throughout gestation. Pair-fed controls received an isocaloric amount of corn starch and chow, with water ad libitum, and ad libitum controls received rat chow and water. On Days 17, 18, 19, and 20 of gestation, the fetuses were weighed and the fetal thyroids were removed for histometric observation. On Days 19 and 20, the fetal thyroids of alcohol-exposed fetuses weighed significantly less than those of the two control groups, but more than the control thyroids 1 day earlier. Maternal alcohol consumption caused a significant decrease in both the follicular cell height and the follicle diameter of the fetal thyroid on all days examined. In the alcohol group on Days 19 and 20 of gestation, the cell height was less than, and the follicle diameter was approximately equal to those in the two controls 2 days earlier. These results indicate that, as a consequence of maternal alcohol consumption, growth of the fetal thyroid gland is retarded, and there are indications of fetal hypothyroidism, as seen from the histometric data. This latter is suggestive of a retarded thyrotropic activity of the fetal pituitary gland.

Alcohol Drinking↗
PubMed1989

Blood modeling using polystyrene microspheres.

The steady flow viscosity at shear rates 0 to 120 sec-1 and dynamic viscoelasticity at frequencies 0.02 to 0.8 Hz were determined for aqueous suspensions of uniform polystyrene microspheres of 1.0 micron diameter. Rheological properties of the microsphere suspensions were Newtonian for particle concentrations up to 32%. By introducing dextran and calcium chloride into the particle suspensions, non-Newtonian behavior was produced similar to that observed for human blood. The cooperative effects of dextran and calcium ions promoted aggregation of particles at a concentration as low as 12%. Thus, a suspension of uniform sized spherical polystyrene particles in aqueous solution of dextran may be made to mimic blood by controlling the surface charge on the polystyrene spheres using addition of calcium ions to the medium.

Blood↗
PubMed1989

[Histological observations of immunosuppressive effects of FK-506 in canine lung allotransplantation].

The Immunosuppressive effects of FK-506 were studied histologically in allotransplanted canine lungs. FK-506 was administered daily in a dose of 0.15 mg/kg after left lung allotransplantation. Nine dogs underwent open lung biopsy on the 7th postoperative day (p.o.d.). Mild mononuclear cell infiltrations around small vessels (MNC cuffings), which suggested an early phase of rejection, were observed in 2 dogs. Two dogs were sacrificed on the 14th and 2 on the 21st p.o.d. MNC cuffings were observed in the lung of one dog and in the bronchial submucosa of 2 dogs. Six dogs were sacrificed on the 28th p.o.d. MNC cuffings were observed in the lungs of 3 dogs and in the bronchial submucosa of 5 dogs. The MNC cuffings were of nearly the same extent in the lung and in the bronchial submucosa of most of the dogs. Alveolar structures were well in all the dogs and the bronchial epithelium in all except 2 of the dogs sacrificed on the 28th p.o.d. preserved. Arterial blood gas was examined before and 20 min. after right hilar ligation in 3 dogs on the 28th p.o.d. The PaO2 (228 mmHg, 312 mmHg, 217 mmHg at FiO2: 0.5, tidal volume: 20 ml/kg, respiratory rate: 20/min) and PaCO2 after rt, hilar ligation indicated that the transplanted lung was functioning well in these dogs. The present study suggests that FK-506 could be a potent immunosuppressive agent in lung transplantation. As 4 of the 14 dogs used in this experiment died from severe diarrhea caused by FK-506, further studies are needed to determine the suitable dose and route of administration of FK-506.

Animals↗
PubMed1989

Crossover study of immunoglobulin replacement therapy in patients with low-grade B-cell tumors.

A randomized crossover study of prophylactic immunoglobulin (IgG) therapy was performed in patients with chronic lymphocytic leukaemia (CLL) or non-Hodgkin's lymphoma (NHL). Twelve patients with hypogammaglobulinemia or a history of recurrent infections received infusions of IgG or placebo intravenously (IV) every 3 weeks for 1 year. They were then switched to the alternative preparation for another year. The number of serious bacterial infections was significantly less (P = .001; Mainland's cross-over method) in the months in which patients received IgG. Serious bacterial infections showed a trend to be associated with an IgG level less than 6.4 g/L (P = .046; Fisher's exact test).

Aged↗
PubMed1989

Factors affecting a cyanogen bromide-based assay of thiamin.

We analyzed extensively a modified thiochrome method for thiamin analysis. Acid phosphatase (EC 3.1.3.2) from potato was superior to either alpha-amylase or acid phosphatase from wheat germ as a dephosphorylating agent. Timing of cyanogen bromide exposure was important, but the assay had good precision and accuracy. The standard curve was linear from 10 to 3000 nmol/L. The within-run and between-run coefficients of variation for total thiamin in whole blood were 3.6% and 7.4%, respectively. Analytical recoveries for low, intermediate, and high additions of thiamin to whole blood were 93-109%. Sample yield was increased by 41% (+/- 29% SD) with pre-assay freezing. Samples were stable for two days at room temperature, for seven days when refrigerated, and for two years when frozen. Previously unreported interference was seen with penicillin derivatives, and with several commonly used diuretic and antiepileptic medications. This assay may be suitable for population screening; 200 samples could be analyzed weekly at a cost of +0.20 per sample.

Acid Phosphatase↗
PubMed1989

Klebsiella pneumoniae bacteremia in the community hospital.

The purpose of this study was to elicit the circumstances of occurrence and organism sensitivities of Klebsiella pneumoniae bacteremia in the community hospital, since data on this illness from the community hospital are rare. All records of documented Klebsiella pneumoniae bacteremia (46 cases) at Alachua General Hospital, Gainesville, Florida, over the period July 14, 1982, through July 27, 1985, were reviewed in detail. Fifty-nine percent (27 organisms) were nosocomial, whereas 41% (19 organisms) were community acquired. The most common predisposing disorders in these patients were, in decreasing order, malignancy; following gastrointestinal or biliary surgery; biliary tract obstruction; diabetes; and unknown. Twenty-two percent (10) of the patients died from bacteremia. The majority of organisms tested were sensitive to mezlocillin, cephalothin, cefoxitin, tetracycline, tobramycin, gentamicin, co-trimoxazole and ceftizoxime. Therapy was considered to be appropriate in 89% (41) of the patients and inappropriate in 10.9% (5) of the patients. Contrary to previous thought, Klebsiella pneumoniae bacteremia is a relatively common problem in the community hospital and may be community acquired as well as nosocomial. There are many characteristics of this disease in the community that are different from those reported in studies on Klebsiella pneumoniae bacteremia from large referral centers.

Adult↗
PubMed1989

Sodium dodecyl sulfate-glycerol polyacrylamide slab gel electrophoresis for the resolution of apolipoproteins.

We describe the resolution of the plasma apolipoproteins with molecular weights from 8,800 to greater than 550,000, using a 3.5% sodium dodecyl sulfate-glycerol polyacrylamide slab gel system. The simplicity of this system and the resolution of proteins over a broad range of molecular weights will make it particularly useful in investigations of apolipoprotein composition of plasma lipoproteins.

Apolipoproteins↗
PubMed1989

Pneumobelt for sleep in the ventilator user: clinical experience.

A pneumobelt with a positive pressure respirator was used for sleep for three patients with chronic respiratory insufficiency secondary to syringomyelia, poliomyelitis, and Friedreich's ataxia respectively. This device was found to be effective in improving and maintaining their daily functioning in the community or institute.

Chronic Disease↗
PubMed1988

On the time-dependent diffusion of macromolecules through transient open junctions and their subendothelial spread. I. Short-time model for cleft exit region.

In this two-part study we shall quantitatively study, using time-dependent models, the hypothesis that transient open junctions associated with widely scattered endothelial cells undergoing mitosis are the structural equivalent for the large pore pathway via which macromolecules the size of albumin or larger cross the vascular endothelium. In an earlier steady-state model [Am. J. Physiol. 248, H945-960 (1985)], the authors demonstrated that such an open-junction pathway could quantitatively account for the regional differences in macromolecular permeability observed in various mammalian arteries in regions of enhanced cell turnover as indicated by 3H-thymidine although these cells were less than 1% of the population and the open junctions occupied less than 10(-5) of the endothelial surface. The time-dependent models described herein have been used to identify a time window and size of probe molecule wherein this hypothesis could be tested experimentally in the larger blood vessels. The first stages of these experiments have now been completed and provide convincing evidence that the junctions of virtually all endothelial cells in the M phase of the cell cycle are leaky to macromolecules (Lin et al., 1988). The statistical frequency of such leakage sites has also been determined. The time-dependent models developed herein contain two important refinements that were not contained in the earlier steady state model. First the finite resistance of the open cleft as a function of molecular size is accounted for by introducing a diffusion coefficient ratio Dj/Dz describing the relative resistance of the open cleft compared to the subendothelial tissue in the direction normal to the endothelial surface. Second the non-isotropy of the vessel wall due to the elastic lamina is considered by introducing a second diffusion coefficient ratio Dx/Dz describing the relative resistance in the lateral as compared to the normal direction. This second ratio can be as large as 100 for the arterial intima, but is of order unity for capillaries. In Part I a short time model is presented to describe the initial labeling of the open cleft and the subendothelial space in the vicinity of the cleft exit following the introduction of a tracer macromolecule. This model is valid for both larger vessels and capillaries since wall thickness and curvature and the interaction between leakage sites does not enter into the model description. In Part II (Wen et al., 1988) a long-time model is developed for larger vessels only which is valid for greater times including steady-state labeling.

Albumins↗
PubMed1988

The beta very low density lipoprotein present in hepatic lipase deficiency competitively inhibits low density lipoprotein binding to fibroblasts and stimulates fibroblast acyl-CoA:cholesterol acyltransferase.

Beta very low density lipoprotein (VLDL) was isolated from a patient with hepatic lipase deficiency. The particles were found to contain apolipoprotein B-100 (apoB) and apolipoprotein E (apoE) and were rich in cholesterol and cholesteryl ester relative to VLDL with pre beta electrophoretic mobility. These particles were active in displacing human low density lipoprotein (LDL) from the fibroblast apoB,E receptor and produced a marked stimulation of acyl-CoA:cholesterol acyltransferase. Treatment of intact beta-VLDL with trypsin abolished its ability to displace LDL from fibroblasts. Incubation of trypsin treated beta-VLDL with fibroblasts resulted in a significant stimulation of acyl-CoA:cholesterol acyltransferase activity. beta-VLDL isolated from a patient with Type III hyperlipoproteinemia and an apoE2/E2 phenotype had a higher cholesteryl ester/triglyceride ratio than the beta-VLDL of hepatic lipase deficiency and contained apoB48. It displaced LDL from fibroblasts to a small but significant extent. The Type III beta-VLDL stimulated acyl-CoA:cholesterol acyltransferase to a level similar to that of trypsin-treated beta-VLDL isolated from the hepatic lipase-deficient patient. These results demonstrate that the cholesterol-rich beta-VLDL particles present in patients with hepatic lipase deficiency are capable of interacting with fibroblasts via the apoB,E receptor and that this interaction is completely due to trypsin-sensitive components of the beta-VLDL. These particles were very effective in stimulating fibroblast acyl-CoA:cholesterol acyltransferase. This stimulation was due to both trypsin-sensitive and trypsin-insensitive components.

Apolipoproteins↗
PubMed1988

Differential effects of N-methyl-D-aspartic acid and L-homocysteic acid on cerebellar Purkinje neurons.

The effects of N-methyl-D-aspartic acid (NMDA) and L-homocysteic acid (LH) were measured on cerebellar Purkinje neurons. In urethane-anesthetized rats, iontophoretic application of NMDA elicited 3 different effects on the spontaneous activity of Purkinje cells: excitation, inhibition and biphasic responses consisting of excitation followed by inhibition. On the other hand, LH elicited excitation, only, regardless of the actions of NMDA on the same neurons. We also examined the effects of various excitatory amino acid antagonists on NMDA- and LH-mediated responses. Excitatory effects of NMDA were antagonized effectively by D.L-2-amino-5-phosphonovalerate (APV), ketamine, gamma-D-glutamylglycine (DGG), D,L-2-amino-7-phosphonoheptanoate (APH), and were not influenced significantly by L-glutamate diethylester (GDEE). Inhibitory responses of NMDA were antagonized by APV, APH and ketamine. LH-mediated excitations were influenced significantly by DGG and ketamine whereas GDEE, APV and APH failed significantly to attenuate the effects of LH. Based on the differential actions of LH and NMDA and the selectivity of NMDA antagonists for NMDA rather than LH-mediated excitations, it appears that the major actions of LH may not be mediated through NMDA receptor sites, at least in the cerebellum.

2-Amino-5-phosphonovalerate↗