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Biomedical subjects

M Lewis

Publications and source records attributed to M Lewis.

At least 343 records · Page 19Linked to original sources
PubMed1988

Calcium retention and increased vascular reactivity caused by a hypothalamic sodium transport inhibitor.

1. Using a previously established method of isolating an active-sodium-transport inhibitor (ASTI) from hypothalamic cell culture medium, the inhibitor was isolated and partially purified from sequential passages through Sephadex G-25 and h.p.l.c., and its effects on de-endothelialized rabbit aortic strips were investigated. 2. ASTI caused a cumulative concentration-dependent increase in tension which reversed slowly after wash, and the wash showed an identical effect on fresh strips. 3. Ouabain, used as a control, also caused a concentration-dependent increase in tension which reached a plateau at a concentration of 10 mmol/l. Both ouabain and ASTI caused a significant potentiation of the vasoconstrictor effect of noradrenaline at concentrations of 1 nmol/l-0.1 mmol/l. 4. Both ASTI and ouabain caused a significantly greater (P less than 0.01) calcium retention than control medium in aortic strips. 5. Incubation of ASTI with prolidase, chymotrypsin and carboxypeptidase A destroyed the vasoconstrictor effects as well as its inhibitory effects on sodium, potassium-dependent adenosine triphosphatase and sodium efflux from erythrocytes, but leucine aminopeptidase was ineffective. 6. These studies suggest that hypothalamic cells in culture release a peptidic inhibitor of active sodium transport which increases vascular reactivity, potentiates vasoconstrictor effects of noradrenaline and causes calcium retention.

Animals↗
PubMed1988

Some observations of levels of plasma cholinesterase activity within an obstetric population.

An account of plasma cholinesterase activity in samples of maternal and cord blood is presented. It is confirmed that plasma exchange markedly reduces the level of activity in maternal blood, and that the level is further reduced during the first 3-4 postnatal days. A particularly marked decrease was found in those cases in which spontaneous mid-trimester abortion occurred. The level of activity in maternal blood (excluding mothers subjected to plasma exchange) at the time of delivery, was higher than that in cord blood in 61% of cases. In 23% of cases the level of activity was appreciably (0.05 units) higher in cord blood, and two-thirds of these cord samples contained the E2+ electrophoretic variant of plasma cholinesterase. The mean levels of activity in maternal and cord blood of Rhesus negative patients were significantly lower than those among Rhesus positive patients but there was no such distinction between Rhesus positive and Rhesus negative males and nonpregnant females. We encountered an incidence of 1:228 abnormal phenotypes in a series of 1593 mothers who underwent Caesarean section under a technique of general anaesthesia which included a suxamethonium infusion. However, probably only two of the seven patients would definitely be sensitive when not pregnant.

Anesthesia, General↗
PubMed1988

Progressive loss of fibronectin-mediated opsonic activity in plasma cryoprecipitate with storage. Role of fibronectin fragmentation.

Septic injured patients often manifest a deficiency of plasma fibronectin. Several studies have shown improvements in organ function in such patients following infusion of fibronectin-rich plasma cryoprecipitate, while other studies found no improvement. One explanation for these differences may be the use of plasma cryoprecipitate which has been stored for various time intervals prior to its use as a source of fibronectin. This investigation tested the hypothesis that the opsonic activity of fibronectin in cryoprecipitate may decline with increased storage duration. Using a bioassay of opsonic activity, we evaluated human plasma cryoprecipitate that was stored at either -20 or -80 degrees C for various intervals (2 weeks to 12 months) after its preparation from fresh donor plasma. Our findings demonstrated that the opsonic activity of fibronectin in cryoprecipitate declined with increasing time of storage. Significant loss (p less than 0.05) of opsonic activity was first evident after 2 months of storage. Storage at -80 degrees C did not prevent this decline in opsonic activity as compared to storage at -20 degrees C. Immunoblot analysis revealed extensive fragmentation of the dimeric fibronectin (440 kdaltons) and the presence of lower molecular weight fragments in 4- to 12-month-old plasma cryoprecipitate. Therefore, plasma cryoprecipitate of varying ages (storage time) when used as a source of fibronectin for replacement therapy to support phagocytic function in septic injured patients may result in different fibronectin-mediated responses. The decline in activity may be due, in part, to fragmentation of the fibronectin molecule.

Biological Assay↗
PubMed1988

The Swann phenotype 700:4,-41; genetic studies.

Serological analysis of the red cells from members of a large French-Canadian kindred proved that the Swa antigen is not part of the P1, Dombrock or Yt blood group systems. A linkage analysis of the SW blood group locus in relation to 27 other loci indicates that SW is not closely linked to ABO, ACP1, ADA, AK1, C3, D2S5, DO, ESD, F13A, FY, GLO1, GPT, HP, IGHG, JK, LU, MYCL, P1, PGP, PGM1, PLG, RH or YT. By inference the study also allows exclusion of Swa from the Landsteiner-Wiener, Radin and Scianna blood group systems and exclusion of SW from the p22.1 to p34 segment of chromosome 1.

Blood Group Antigens↗
PubMed1988

The chromosome 19 linkage group LDLR, C3, LW, APOC2, LU, SE in man.

The data establish linkage in both sexes for LDLR:LW (zeta = 8.43 at theta = 0.00) and in the male for LDLR:LU (zeta = 3.31 at theta = 0.00) and for LW:APOC2 (zeta = 3.90 at theta = 0.00). They confirm LDLR:C3 and APOC2:LU linkage in both sexes, and LW:LU linkage in the male. The loci constitute two tightly linked gene clusters, LDLR, C3, LW and APOC2, LU, SE, distinguished by measurable linkage in female meioses within but not between clusters. Argument is supported for a 19p13.2-cen position for LW and a long arm position for LU and SE.

Apolipoprotein C-II↗
PubMed1988

Occult biochemical pregnancy: fact or fiction?

Daily urine samples were obtained from 38 women of proven fertility, who were attempting to conceive, to assess the frequency of clinically unsuspected "biochemical pregnancies' on the basis of late luteal phase rises of hCG. In 25 clinically confirmed conception cycles, the earliest pregnancy-induced hCG rises from baseline occurred 8 days after the endocrinologically defined date of ovulation (mean 11.1 days, SD 1.3). Urine samples obtained throughout 50 non-conception ovulatory cycles provided no evidence of any 'biochemical pregnancies' on the basis of late luteal phase rises of hCG occurring 8 or more days after the endocrinologically defined date of ovulation. If, as in previous studies, the date of ovulation had been estimated on the basis of menstrual cycle length and only the relatively non-specific NIH antiserum had been used in RIAs, 7 of the 50 (14%) cycles would have been classified as resulting in biochemical pregnancies on the basis of hCG greater than 50 m-i.u./ml on one occasion or greater than 20 m-i.u./ml on two or more occasions after day 20 of the cycle. These levels of 'hCG' occurred at or soon after ovulation and could be explained by LH cross-reacting in the RIA. The rises of 'hCG' were not confirmed when the urine samples were retested with an antiserum (Wellcome 895) of very high specificity for hCG. These results raise the possibility that the frequency of clinically unsuspected 'biochemical pregnancy' may have been substantially overestimated.

Adult↗
PubMed1988

Serial neuropsychological follow-up of a child following craniospinal irradiation.

Serial neuropsychological examinations were made of an eight-year-old girl following diagnosis and treatment of a pineocytoma. The tumor was resected and she received intensive radiation therapy to the entire neuraxis, with a boost to the pineal region. A battery of neuropsychological tests was administered every six to eight weeks, beginning before and continuing for 48 weeks after radiation therapy. Parental questionnaires on the patient's everyday behavior were obtained, as well as past and present school records. MRI studies were performed seven weeks, nine months and 14 months after treatment had ended. The only functional area showing deterioration over the follow-up period was memory, both verbal and spatial. The MRIs showed no abnormalities related either to the tumor or to the radiation therapy.

Brain↗
PubMed1988

[The myocardial infarct status of a South German population: results of the Augsburg myocardial infarct register l985].

The Augsburg Myocardial Infarction Register recorded in 1985, 999 coronary events (734 men, 265 women) occurring in 25-74-year-old residents of the city of Augsburg and the counties of Augsburg and Aichach-Friedberg (study population: 156,489 men and 171,093 women). On average, 444 men and 138 women per 100,000 of the population suffered an acute myocardial infarction (AMI) in 1985. The risk of morbidity increased with age in both men and women, but gained significance for women only after their 55th year of life. The 28-day case fatality was 54% for male AMI cases and 66% for females; 34% of the AMI patients died without ever reaching a hospital. Cardiopulmonary resuscitation (CPR) was attempted by a physician in one-in-three of these out-of-hospital deaths. Although one of two out-of-hospital deaths occurred in the presence of a medical lay person; lay CPR was the exception. Broader population education in CPR techniques may thus constitute one method of reducing the number of early AMI deaths. The median prehospital time for interviewed hospital patients (66%) was 5 h, and approximately 2 h for patients with systemic thrombolysis (n = 71). The combination of fatal coronary events from the official cause-of-death statistics and the results from the Augsburg register were used to estimate AMI morbidity for the whole of the FRG in 1985. This leads to an expected morbidity of 210,000 AMI, of which 141,000 AMI will be fatal (both sexes).

Adult↗
PubMed1988

Adriamycin custom-tailored immunoconjugates in the treatment of human malignancies.

Twenty-three patients with disseminated refractory malignancies each received a tailored combination of adriamycin-conjugated murine monoclonal antibodies. Tumors were typed using a panel of antibodies. Cocktails of up to six antibodies were selected based on binding greater than 80% of the malignant cells as tested by immunoperoxidase and flow cytometry. These monoclonal antibodies were then conjugated to Adriamycin and administered intravenously. Seventeen of 23 patients had reactions to the administration of immunoconjugates, but these were tolerable in all but two patients. Fever, chills, pruritus, and skin rash were by far the most common transitory reactions. All were well controlled with premedication. In several patients there was limited antigenic drift among various biopsies within the same patient over time. This observation confirms the necessity for the use of a cocktail of antibodies if one wishes to cover all tumor cells. Preliminary serologic evidence suggests that the development of an IgM antibody, which is specific against the mouse monoclonal antibody, has the specificity and sensitivity to predict clinical reactions. Selected patients were re-treated. One patient with chronic lymphocytic leukemia had re-treatment on three occasions and demonstrated regression of peripheral lymph nodes. Two patients with breast carcinoma had definite improvement in ulcerating skin lesions and two patients with tongue carcinoma had shrinkage of their lesions. In the course of the study free Adriamycin released from the monoclonal antibodies was discovered to be a limiting factor in the amount of antibody that could be administered. Up to 1 g of Adriamycin and up to 5 g of monoclonal antibody were administered. The limiting factor appeared to be a variable dissociation of active Adriamycin from the antibody that unpredictably caused hemopoietic depression. This study demonstrates the feasibility and reviews technical considerations in preparing immunoconjugate cocktails for patients with refractory malignancies. The major technical hurdle appears to be the selection of an effective conjugation method that can be used to optimally bind Adriamycin to monoclonal antibodies for targeted cancer therapy.

Animals↗
PubMed1988

Computer-analyzed dietary intake printouts: guidelines for their design and student comprehension.

The purpose of this study was to determine the ability of individuals to comprehend and interpret information on nutrient analysis computer program printouts and to assess their understanding of certain concepts closely related to such printouts, specifically the Recommended Dietary Allowances (RDAs) and vitamin and mineral supplementation. The study sample comprised 553 college students who were randomly assigned to one of seven groups. Each group received a nutrient analysis computer printout that varied in terms of type, amount, and format of information supplied. Printouts with varying characteristics were used in order to identify those elements that contributed to the greatest and most correct understanding and interpretation. A 30-item objective knowledge test was used to assess understanding and ability to interpret information on the printouts. Research results indicate that most individuals had misconceptions concerning the RDAs and vitamin and mineral supplementation. Recommendations were made for improving the information provided on printouts regarding these two topics. Subjects had little difficulty in reading the printout correctly. However, groups whose printouts included only nutrient data generally had more difficulty using the information to draw appropriate conclusions and identify ways to improve dietary intake than did individuals whose printouts included short messages listing sources and functions of nutrients. Data presented in graphic format were more easily understood than data in spreadsheet form. Eight design recommendations intended to assist nutritionists and software designers in selecting and/or creating printouts were made on the basis of the results of this study.

Computer Graphics↗