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Biomedical subjects

C C Lin

Publications and source records attributed to C C Lin.

At least 559 records · Page 31Linked to original sources
PubMed1986

The meiotic segregation of human sperm chromosomes in two men with accessory marker chromosomes.

Accessory marker chromosomes are occasionally discovered in normal individuals and they are presumed "clinically inert" since they do not appear to have any phenotypic effect. However, they do pose a theoretical risk at meiosis since they could disrupt the normal pairing and disjunction of homologous chromosomes. Sperm chromosome complements have been studied in two normal males, each of whom carry a small bisatellited accessory marker chromosome 47,XY, + mar (psps), to determine if these marker chromosomes are associated with an increased frequency of aneuploid gametes. Pronuclear chromosomes were visualized after in vitro fertilization of golden hamster eggs with human sperm. The frequency of sperm complements containing a marker chromosome was not significantly different from 50% as theoretically expected, in either male (17/43 and 13/31 with marker chromosomes). One male had 2/43 (4.7%) aneuploid sperm, which is very close to the average frequency of aneuploid sperm seen in control donors (5%). The other male had 6/31 complements with chromosomal abnormalities. One set of sperm chromosomes had structural abnormalities, and five (16.1%) had numerical abnormalities. This frequency of aneuploidy is significantly elevated over the frequency seen in control donors (P = .0002). It is particularly interesting that all the abnormalities involved small chromosomes, as would be expected if the marker chromosome participated in distributive pairing and thereby disrupted normal disjunction of chromosomes of similar size. These preliminary results suggest that accessory marker chromosomes may increase the risk of aneuploid gametes in some individuals.

Adult↗
PubMed1986

Brachial artery stenosis secondary to ergotism and responsive to nifedipine.

Ergotism is an uncommon drug reaction that may lead to severe ischemic vasoconstriction, which is usually unilateral and more commonly involves the lower extremities. Successful therapeutic measures have included invasive vascular surgery and the use of various available intravenous and oral vasodilators. Reported here is the case of a 56-year-old woman with Marfan's syndrome and chronic migraine headaches who presented with upper extremity pulselessness that responded promptly to oral nifedipine (Procardia). This relatively inexpensive agent with potent peripheral arterial vasodilative properties appears to be the agent of choice in severe ergotamine poisoning.

Arterial Occlusive Diseases↗
PubMed1986

Pharmacokinetics and metabolism of [14C]rosaramicin in dogs.

The pharmacokinetics and metabolism of [14C]rosaramicin were studied in dogs after intravenous (i.v.; 10 mg/kg [bodyweight]) and oral (25 mg/kg) administration. After i.v. administration, rosaramicin levels in plasma declined rapidly, with half-lives of 0.22 h for the distribution phase and 0.97 h for the elimination phase. The apparent volume of distribution was 3.43 liters/kg, and the total body clearance was 106 mg/min . kg, indicating extensive distribution in tissue or metabolism or both. The absorption of oral solution was 58%, and the absolute bioavailability of rosaramicin was 35%. The plasma area under the curve of unchanged rosaramicin was only 5% that of total radioactivity after oral administration and 8% after i.v. administration, indicating extensive metabolism of the drug. The total radioactivity excreted in urine accounted for only 24% of the i.v. dose and 17% of the oral dose. Fecal radioactivity accounted for 71% of the i.v. dose and 68% of the oral dose. Several metabolites were observed in the plasma and urine. The amount of unchanged rosaramicin in urine (1 to 2% of the dose) was quite small after drug administration by either route.

Administration, Oral↗
PubMed1986

Column-switching high-performance liquid chromatographic method for determination of a new antiviral agent, cyclaradine, in serum.

Cyclaradine is a novel carbocyclic nucleoside with good activity against the viruses of the herpes group. To facilitate pharmacokinetic studies on cyclaradine, an automated column-switching high-performance liquid chromatographic (HPLC) method was developed for the determination of cyclaradine in serum. Deproteinized serum containing cyclaradine was directed to an on-line extraction column which retained cyclaradine while many potentially interfering components were eluted to waste. Fourteen minutes later, the switching valve was automatically rotated, permitting an appropriate mobile phase to elute cyclaradine from the extraction column onto an analytical C18 column for further separation and UV detection. The method showed excellent linearity (r = 0.9995) for cyclaradine concentrations ranging from 0.05 to 5 micrograms/ml. It also provided good sensitivity (0.05 micrograms/ml). The assay was precise, with within-run and between-run coefficients of variation of less than 1.90%. The accuracy, expressed as differences between observed values and theoretical values, ranged from -4.12 to 4.80%. The assay involves a simple deproteinization of serum followed by a fully automated sample cleanup, eliminating long and tedious manual extraction prior to HPLC. The column-switching HPLC method has been successfully used for the determination of cyclaradine serum levels in squirrel monkeys following a single oral dose of 20 mg/kg.

Animals↗
PubMed1986

A high-resolution C-banding technique.

A high-resolution C-banding technique is described. The major advantages of this method are its simplicity and reliability. Because this technique allows the recognition of unusual C-band heteromorphisms, it can be very useful in population cytogenetic studies.

Cells, Cultured↗
PubMed1986

Attenuation of natriuretic response to saline loading in AV3V lesioned rats.

Anteroventral third ventricle (AV3V) has been implicated in body fluid balance and blood pressure control. This study thus was to evaluate the renal response to saline loading in rats with and without AV3V lesion. Lesioned rats were prepared by electrolytic ablation 4 weeks prior to experiments. Arterial pressure (AP) and renal excretory responses were measured before and after intravenous infusion of 154 mM NaCl (0.388 ml/min) for 1 hour in anesthetized control and lesioned rats. There were no significant differences in AP (125 +/- 3 vs 121 +/- 3 mmHg) and glomerular filtration rate (GFR; 1.5 +/- 0.1 vs 1.6 +/- 0.3 ml/min/g kw) between control rats and lesioned rats. Saline loading did not significantly change AP and GFR in both groups of rats. In control rats there was a striking natriuretic (delta 2660%) and diuretic (delta 1870%) response to saline loading but the lesioned rats only exhibited 50% of the normal excretory response. A similarly attenuated natriuresis and diuresis was also found in conscious, lesioned rats with oral saline loading. These data suggest that AV3V exerts substantial influence on the regulation of sodium and water balance.

Animals↗
PubMed1986

Studies of natural killer cell activity. I. Normal range of a natural killer cell activity in the healthy Chinese.

This study was undertaken to establish a normal distribution curve for natural killer (NK) cell activity in healthy Chinese. NK cell activity was detected in 123 persons of different age groups, from the newborn to 84 years of age. None had any reported infection. The mononuclear cells were obtained from peripheral blood and cord blood for NK test; K562 cells were used as target cells to assay NK cell activity. The results indicated that cord blood had the lower NK cell activity. Increasing NK cell activity was seen with increasing age. In the 20 year to 49 year range, the NK cell activity reached maximal value. The NK cell activity gradually decreased when the age was greater than 50 years.

Adolescent↗
PubMed1986

Good diabetic control early in pregnancy and favorable fetal outcome.

This study of 74 diabetic pregnant women shows that tight maternal blood glucose control before the 32nd week of gestation significantly reduces the incidence of fetal macrosomia (11%) when compared with that of patients with fair to poor control before the 32nd week of gestation (44%, P less than .05) or with those whose good diabetic control was not achieved until after the 32nd week of gestation (34%, P less than .05). The macrosomic infant produced by a diabetic mother is associated frequently with an elevated amniotic fluid C-peptide level, which shows the evidence of intrauterine fetal hyperinsulinism. The use of tight diabetic control early in pregnancy to reduce the risk of fetal macrosomia and/or neonatal complications is of clinical importance in the management of diabetes in pregnancy.

Amniotic Fluid↗
PubMed1986

Clinical and laboratory characteristics of acute leukemia with the 4;11 translocation.

This report describes the clinical and laboratory features of seven cases of acute leukemia associated with the 4;11 chromosomal translocation. All seven children had acute lymphoblastic leukemia by standard morphologic and cytochemical criteria. Leukemic blasts from six of seven patients were terminal deoxynucleotidyl transferase-positive. Immunologic phenotyping suggested the leukemias were of B cell origin; blasts from five patients expressed HLA-DR and p24 (CD-9 antibody), blasts from three patients expressed B4 (CD-19), and blasts from two patients expressed the common acute lymphoblastic leukemia antigen (CD-10). One patient's leukemic blasts contained cytoplasmic immunoglobulin. Analysis of DNA from four of five patients demonstrated additional evidence of B cell differentiation with heavy-chain immunoglobulin gene rearrangement. When DNA from the four patients with heavy-chain immunoglobulin gene rearrangement was analyzed, one patient's DNA demonstrated light-chain immunoglobulin gene rearrangement. However, flow cytometric analysis of blasts from three patients showed the simultaneous expression of the lymphoid-associated antigen B4 (CD-19) and the myeloid-associated antigen My-1 (X-Hapten). Electron microscopic examination of blasts from one patient that expressed both lymphoid- and myeloid-associated antigens demonstrated ultrastructural characteristics of both lineages. These findings suggest that acute leukemia with the t(4;11) abnormality has mixed lineage characteristics as a result of leukemogenesis in a multipotential progenitor cell or aberrant gene expression later in differentiation. Furthermore, serial analysis of karyotype, immunophenotype, and heavy-chain immunoglobulin genes revealed changes in these biologic markers over time, suggesting continued chromosome rearrangement and gene modulation after the leukemogenic event in cells with the t(4;11).

Acute Disease↗