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Biomedical subjects

A Lin

Publications and source records attributed to A Lin.

216 records · Page 12Linked to original sources
PubMed1976

Micro-scale two-dimensional polyacrylamide gell electrophoresis of ribosomal proteins.

A specially designed apparatus and conditions are described for the rapid analysis of ribosomal proteins by two-dimensional gel electrophoresis on a micro scale. The resolution of proteins in electropherograms is comparable to that obtained with other systems, but because of miniaturization, only 0.5 to 1 mug of each protein is required, and the entire procedure, including electrophoresis in both dimensions, and staining and destaining can be completed in 6 to 7 hours.

Electrophoresis, Polyacrylamide Gel↗
PubMed1974

The identification of the eukaryotic ribosomal proteins homologous with Escherichia coli proteins L7 and L12.

Antibodies were raised against eukaryotic (rat liver) and prokaryotic (E. coli) ribosomal particles and ribosomal proteins. The antisera were characterized and used to determine the identity of the eukaryotic proteins homologous to E. coli L7 and L12. The large subunit of rat liver ribosomes contains two acidic proteins, L40 and L41; they migrate during two-dimensional polyacrylamide gel electrophoresis in a way that mimics the behavior of L7 and L12. Rat liver L40 and L41 were found to be immunologically related to E. coli L7/L12, hence the proteins are likely to share some structural homology.

Animals↗
PubMedDate not supplied

Doxorubicin cardiotoxicity: response of left ventricular ejection fraction to exercise and incidence of regional wall motion abnormalities.

Gated radionuclide ventriculograms were performed to evaluate cardiac function in 53 patients who received doxorubicin treatment for various malignancies (mean dose: 449 +/- 128 mg/m2 BSA). In fourteen patients (Group I) function was evaluated before and after treatment; there was a significant decrease of resting left ventricular ejection fraction after therapy (p less than 0.001). Twenty-two patients (Group II) had serial studies during treatment which also showed a significant fall of resting left ventricular ejection fraction (p less than 0.001). Eighteen patients in Groups I and II had supine exercise studies. A normal exercise response was maintained in the majority of patients. Exercise testing added little to the diagnostic performance when compared to serial resting studies. We found regional wall motion abnormalities (mild apical hypokinesis) at rest by visual inspection in 33 of 36 Group I and Group II patients who had received doxorubicin. In the baseline or initial study, only 4 of these patients demonstrated WMA. In 18 Group I and II patients who were exercised, 3 had wall motion abnormalities during the initial study. All of these patients demonstrated wall motion abnormalities at rest after the second study, however only 7 of 18 demonstrated abnormalities during the exercise study. The results indicate that resting left ventricular ejection fraction declines after doxorubicin treatment. Exercise radionuclide angiography may not increase diagnostic accuracy for the detection of doxorubicin related cardiotoxicity. Regional wall motion abnormalities occur with a relatively high incidence following doxorubicin therapy, more readily detectable at rest. However, the exercise study can distinguish doxorubicin related wall motion abnormalities from those due to coronary artery disease.

Adolescent↗
PubMedDate not supplied

Probing surface structure of sarcin domain on ribosomes of Escherichia coli by complementary oligo DNAs and ribosome-inactivating protein.

The regional structure of the sarcin domain of 23S rRNA of Escherichia coli ribosomes was determined by a combinatory approach of oligo DNA probes and the action of alpha-sarcin. The sarcin domain is protected by a reactive complementary oligo DNA probe against the hydrolytic action of alpha-sarcin. This protective effect is dependent upon the length and the complementary sequence of oligo DNA probes that react to ribosomes. Under UV irradiation and using of the primer extension, nucleotides that contacted by reactive oligo DNA probes were determined. Nucleotides at the 3' side of the domain (positions from G2659 to C2676) were targeted by oligo DNA probes that have their sequences to complement the domain, indicating that the 3' side region was exposed on the surface of ribosomes, whereas nucleotides at the 5' side of stem and extented to two bases at the loop (positions from C2646 to A2654) were not accessible to any oligo DNA probes, implying that the region could be buried in ribosomes. This study also provided evidence that the conformation of the sarcin domain is subjected to alteration if the exposed 3' side of domain is targeted by the reactive DNA probe. The importance of the topological arrangement of the sarcin domain that engages in the translocation event during translation is discussed.

Base Sequence↗
PubMedDate not supplied

The action mode of the ribosome-inactivating protein alpha-sarcin.

Based on the tertiary structure of the ribosome-inactivating protein alpha-sarcin, domains that are responsible for hydrolyzing ribosomes and naked RNA have been dissected. In this study, we found that the head-to-tail interaction between the first amino beta-strand and the last carboxyl beta-strand is not involved in catalyzing the hydrolysis of ribosomes or ribonucleic acids. Instead, a four-strand pleated beta-sheet is indispensable for catalyzing both substrates, suggesting that alpha-sarcin and ribonuclease T1 (RNase T1) share a similar catalytic center. The integrity of an amino beta-hairpin and that of the loop L3 in alpha-sarcin are crucial for recognizing and hydrolyzing ribosomes in vitro and in vivo. However, a mutant protein without the beta-hairpin structure, or with a disrupted loop L3, is still capable of digesting ribonucleic acids. The functional involvement of the beta-hairpin and the loop L3 in the sarcin stem/loop RNA of ribosomes is demonstrated by a docking model, suggesting that the two structures are in essence naturally designed to distinguish ribosome-inactivating proteins from RNase T1 to inactivate ribosomes.

Animals↗
PubMedDate not supplied

Menstrual patterns in women with congenital heart disease.

To examine the extent to which congenital heart disease (CHD) influences ovarian function, 98 women (mean age 32.7 years) were asked to complete a mailed questionnaire regarding their menstrual patterns. Patients were divided into acyanotic (60%) and cyanotic (38.8%) groups. Cycle lengths, duration of menstrual cycle, regularity of menses, amount of flow, and breakthrough bleeding were compared in these two groups and against age-matched controls. The mean age of menarche for the sample (13.4 years) was significantly different (p < 0.004) when compared to their controls (12.5 years). With the exception of breakthrough bleeding, statistical differences were not found between the study population and the controls. When the menstrual histories of cyanotic women were compared with those of acyanotic women, differences were found for all categories of menstrual patterns with the exception of the amount of menstrual flow. Menstrual patterns of cyanotic women compared to controls were found to be significantly different for all categories with the exception of amount of flow. In general, women with CHD have menstrual patterns similar to those in the general population.

Adolescent↗
PubMedDate not supplied

Inflammatory markers in younger vs elderly normal volunteers and in patients with Alzheimer's disease.

BACKGROUND: Recently it has been reported that activation of the inflammatory response system (IRS) may play a role in the aging process and in the pathogenesis of the degenerative changes associated with Alzheimer's disease (SDAT). The aims of the present study were to examine the peripheral IRS in normal aging and in SDAT patients. METHODS: Serum zinc (Zn), total serum protein (TSP), albumin (Alb), SP electrophoresis, and serum interleukin-6 (IL-6) and the stimulated production of tumor necrosis factor-alpha (TNFalpha) were determined in younger versus elderly healthy subjects and in SDAT patients vs. age-matched, healthy volunteers. RESULTS: Serum Zn and Alb were significantly lower in elderly than in younger healthy volunteers and were significantly and inversely correlated with age. The production of TNFalpha was significantly higher in elderly than in younger healthy volunteers and was significantly and positively correlated with age. In SDAT patients, no significant changes in serum Zn or TNFalpha production could be found. Serum Alb was significantly lower and serum IL-6 and the alpha1 and alpha2 globulin fractions significantly higher in SDAT patients than in controls. CONCLUSIONS: Activation of the IRS appears to accompany the normal aging process, i.e. lower serum Zn and Alb and increased TNFalpha production, as well as SDAT, i.e. lower serum Alb and increased serum IL-6 and alpha1 and alpha2 globulin fractions. The findings suggest that not all indicators of IRS activation in SDAT are related to those of the normal ageing process.

Adult↗
PubMedDate not supplied

Effects of pregnancy and delivery on serum prolyl endopeptidase (PEP) activity: alterations in serum PEP are related to increased anxiety in the early puerperium and to postpartum depression.

BACKGROUND: There is now some evidence that anxiety or anxiety disorders are related to increased activity of serum prolyl endopeptidase (PEP) and that major depression is related to lower serum PEP. The aims of the present study were to examine (i) the effects of pregnancy and delivery on serum PEP and (ii) the relationships between serum PEP and postpartum depression, anxiety in the early puerperium and a past history of depression. METHODS: Serum PEP activity was measured in 11 healthy nonpregnant and in 98 pregnant women 3 days before delivery and 1 and 3 days after delivery. On the same occasions, pregnant females completed the Spielberger State Anxiety Inventory (STAI) and were divided into high and low anxiety responders, as defined by changes in the STAI. The presence of a previous depression and postpartum depression within 3 months of delivery was assessed by means of DSM-IV criteria. RESULTS: Serum PEP activity was significantly higher 1 and 3 days after delivery than before. Women with a past history of depression as well as anxiety responders had significantly increased serum PEP activity over nonpregnant women and puerperae with a negative history and anxiety nonresponders, respectively. Parturients who developed a postpartum major, but not minor, depression had significantly lower serum PEP than parturients without postpartum depression. The results were controlled for maternal and labor variables, such as type of analgesia and delivery, induction of labor, breast feeding, parity, and duration of pregnancy and labor. CONCLUSIONS: Our results show that, in puerperae, increased serum PEP is related to increased state anxiety in the early puerperium and that lowered serum PEP is related to a subsequent postpartum major depression. INTERPRETATION: The results suggest that increased serum PEP may be related to postpartum anxious blues and that lowered serum PEP may predispose toward postpartum major depression.

Adult↗
PubMedDate not supplied

An in vivo method for the quantitative evaluation of local anesthetics.

We describe a mouse model for evaluation of skin anesthesia after infiltration of local anesthetic. The method involves subcutaneous injection of the anesthetic over the abdomen, and monitoring the vocalization response to electrical stimulus as a measure of analgesia. Prior to drug injection, the vocalization threshold was determined. Mice that vocalized at < or = 8 mA were included in the study. The model was tested using representative agents of the two classes of local anesthetics, bupivacaine, an amide, and chloroprocaine, an ester. The time course and dose response were assessed after injection. The median analgesic time was 15, 40, and 55 min for 0.015%, 0.0625%, and 0.25% bupivacaine and 30, 50, and 55 min for 0.125%, 0.25%, and 2.0% chloroprocaine, respectively. Statistical analysis of the data showed that this method is sufficiently sensitive to detect differences between the dose and duration of local anesthesia (p<0.05, by log rank test of the survival curves). To further validate the model, we compared the duration of anesthesia between the 0.5% bupivacaine and a new long-acting liposomal formulation of 2% bupivacaine. The results showed that the new formulation significantly prolonged the duration of anesthesia (p<0.05). This simple and reliable method may facilitate research on the pharmacology of infiltration anesthesia and the development of new local anesthetics and/or formulations.

Abdomen↗
PubMedDate not supplied

Donor platelet response and product quality assurance in plateletpheresis.

Retrospective analysis of 352 donors who underwent plateletpheresis at least four times, each using the Haemonetics Model 30 Blood Processor, indicated that a postpheresis platelet count of less than 100,000/microliter occurred in only 2.7 per cent of phereses. Restricting pheresis to those with a prepheresis platelet count of greater than 150,000/microliter would have lowered this to 1.3 per cent and eliminated only 3.7 per cent of donations. The donors' platelet counts returned to baseline approximately four days and rebounded above baseline eight to eleven days after pheresis. To minimize the chance of a donor having a postpheresis platelet count less than 100,000/microliter, the prepheresis platelet count should be greater than 150,000/microliter. A platelet count greater than 150,000/microliter immediately following the previous pheresis can be used instead of the prepheresis platelet count. The yield was related to the prepheresis platelet count, number of cycles, sex, type of procedure (platelet or platelet-leukapheresis), and the yield recorded during an individual's previous procedures. Seventy-five per cent of plateletpheresis products contained more than 3.3 x 10(11) platelets. This might be a satisfactory standard for quality assurance.

Blood Donors↗
PubMedDate not supplied

Plasma separation using a hollow fiber membrane device.

A disposable hollow fiber device was evaluated by collecting approximately 550 ml of normal donor plasma (n = 43) and by performing sham (n = 10) and therapeutic (n = 12) plasma exchanges. Blood was processed at 70 ml per min, and plasma flux averaged 23 (collection) and 25 (exchange) ml per min (mean separation efficiencies of 52 and 60%, respectively). The procedures were tolerated well by all donors and patients. The plasma hemoglobin concentration in separated plasma averaged 1 mg per dl, and cell contamination was negligible (mean of 1, 3, and 6 RBCs, platelets and WBCs/microliter, respectively). There was no evidence of in vivo classical or alternative pathway complement activation as assessed by total hemolytic complement generation (CH50), alternative pathway hemolytic activity (AP50), C3 conversion, or C5 activation, nor were unexpected changes seen in the results of laboratory tests performed after the procedure. Sieving coefficients during sham plasma exchange averaged as follows: albumin, 1.03; IgM, 1.0, IgG, 1.0; IgA, 0.98; factor V, 1.07; factor VII, 0.89; factor VIII, 1.05; and factor IX, 1.19. The device appears to be useful for separation of cell-free plasma from blood during therapeutic plasma exchange procedures.

Blood Component Removal↗
PubMedDate not supplied

MR spectroscopy in neurocysticercosis.

MR spectroscopy findings in a case of neurocysticercosis are presented. A combination of elevated lactate, alanine, succinate, and choline levels and reduced levels of N -acetylaspartate and creatine in a cystic intraaxial lesion in the brain helped in characterizing the lesion. To our knowledge, the short echo point resolved spectroscopic sequence (PRESS) spectrum of neurocysticercosis, as described in our case, has not been reported before.

Adult↗