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Biomedical subjects

G Richardson

Publications and source records attributed to G Richardson.

At least 109 records · Page 6Linked to original sources
PubMed1989

Prenatal exposure to alcohol: effect on infant growth and morphologic characteristics.

In this prospective study of alcohol and other substance use during pregnancy, a cohort of 650 women was interviewed at each trimester of pregnancy. Data are presented concerning the status of 595 live singleton births. A relationship was demonstrated between prenatal maternal alcohol use and growth and morphologic abnormalities in the offspring. Low birth weight, decreased head circumference and length, and an increased rate of fetal alcohol effects were all found to be significantly correlated with exposure to alcohol during the first 2 months of the first trimester.

Abnormalities, Drug-Induced↗
PubMed1988

Plasma from myasthenia gravis patients reduces acetylcholine receptor agonist-induced Na+ flux into TE671 cell line.

Plasma from myasthenia gravis patients was tested for its ability to inhibit agonist-induced 22Na+ influx into the TE671 cell line that expresses human acetylcholine receptors. Reduced 22Na+ influx correlated weakly with the total anti-acetylcholine receptor antibody level in the plasma, and was also related to the presence of antibody directed against the agonist binding site, as detected by inhibition of 125I-alpha-bungarotoxin binding. However, in some cases there was inhibition of 22Na+ flux without evident anti-alpha-bungarotoxin binding site antibody. We conclude that in most patients antibodies that interfere with 22Na+ influx do so by blocking the agonist binding site. However, in some cases antibodies may be directed at the Na+ ion channel or some important functional determinant.

Adult↗
PubMed1986

Characterization of immune response to oral administration of Streptococcus sobrinus ribosomal preparations in liposomes.

Gnotobiotic rats gastrically intubated with a total of 12.5 micrograms of Streptococcus sobrinus ribosomal protein incorporated into cholesterol-based liposomes had significantly (P less than or equal to 0.01) fewer carious lesions on their molar surfaces than did nonimmunized infected controls after challenge with a virulent organism. The immunized animals had significantly (P less than or equal to 0.01) lower numbers of molar-adherent S. sobrinus cells and higher levels of salivary immunoglobulin A antibodies to S. sobrinus whole cells and ribosomes than did the control group. Dose-response studies indicated that 12.5 micrograms of S. sobrinus ribosomal protein in liposomes induced slightly higher immune responses than did 62.5, 125.0, and 250.0 micrograms of ribosomal protein incorporated into liposomes. Intubation of rats with up to 250.0 micrograms of S. sobrinus ribosomal protein alone was no more effective in reducing the numbers of molar-adherent S. sobrinus cells than were nonimmunized infected controls, establishing that insertion of ribosomes into liposomes was required for inducing an effective immune response. These results indicate that oral administration of as little as 12.5 micrograms of S. sobrinus ribosomal protein incorporated into liposomes can protect rats from caries formation after challenge with the virulent organism by inducing specific salivary immunoglobulin A antibodies which can inhibit colonization by the challenged S. sobrinus.

Administration, Oral↗
PubMed1985

The suitability of a membrane diffusion growth chamber for studying bacterial interaction.

Rates of diffusion of nutrients and metabolites through 0.1 micron pore diameter polycarbonate membranes are so low that the use of membrane-separated systems to study bacterial interaction seems to have little application. Effective nutrient availability throughout the system is very dependent on membrane area/medium volume ratio. An attempt to demonstrate a known interaction in the membrane diffusion chamber was not successful.

Bacteria↗
PubMed1984

Word recognition under spatial transformation in retarded and normal readers.

The recognition of words in normal, reversed, and inverted orientation was compared in a group of 9- to 11-year-old retarded readers and a matched group of normal readers. Using the ratio of reading times as an index of reading difficulty under spatial transformation, the results confirmed those of earlier studies which have shown that retarded readers' performance is less affected by spatial transformation than is normal readers'. However, an analysis in terms of the ratio of numbers of words read correctly pointed to just the opposite conclusion. The two sets of findings were reconciled by showing that they follow from the form of the function relating reading time to number correct, and by demonstrating that when word lists are equated for orthographic familiarity the performances of retarded and normal readers are equally affected by spatial transformation, whether the time or number ratio is used as an index.

Child↗
PubMed1981

Delayed sleep phase syndrome. A chronobiological disorder with sleep-onset insomnia.

We describe a new syndrome called "delayed sleep phase insomnia." Thirty of 450 patients seen for a primary insomniac complaint had the following characteristics: (1) chronic inability to fall asleep at a desired clock time; (2) when not on a strict schedule, the patients have a normal sleep pattern and after a sleep of normal length awaken spontaneously and feel refreshed; and (3) a long history of unsuccessful attempts to treat the problem. These patients were younger than the general insomniac population and as a group did not have a specific psychiatric disorder. Six patients' histories are described in detail, including the successful nonpharmacological chronotherapy regimen (resetting the patients' biological clock by progressive phase delay). Delayed sleep phase insomnia is proposed to be a disorder of the circadian sleep-wake rhythm in which the "advance" portion of the phase response curve is small.

Adolescent↗
PubMed1980

The use of silastic foam dressing in the treatment of advanced hidradenitis suppurativa.

We describe our experience in the use of a Silastic foam dressing in 17 patients undergoing radical excision of hidradenitis suppurativa whose wounds were allowed to heal by granulation. Axillary excisions were carried out in 9 patients and perineal excisions in 8 patients. The technique permits adequate excision of the disease and results in a cosmetically acceptable scar, superior to that obtained by skin grafting and with little limitation of movement. It avoids the pain of conventional management of granulating wounds by gauze packing. It is considered that this method of management is superior in most respects to other techniques used to manage the defect resulting from adequate excision of hidradenitis.

Adolescent↗
PubMed1980

Serum cefazolin levels during cardiopulmonary bypass.

This study was done to assess the adequacy of a regimen using cefazolin as a prophylactic antibiotic for patients undergoing open-heart operation. At the time of the preoperative medication, adult patients received 1 gm of cefazolin intramuscularly, and pediatric patients were given a dose of 20 mg per kilogram of body weight. Group I consisted of 10 adults undergoing a variety of cardiac procedures. The mean serum cefazolin level after institution of cardiopulmonary bypass was 27.36 micrograms/ml (range, 13.1 to 40.3 micrograms/ml). This level remained fairly stable throughout cardiopulmonary bypass. Group II consisted of 10 pediatric patients undergoing cardiac procedures for repair of a variety of congenital anomalies. The mean serum cefazolin level after institution of cardiopulmonary bypass was 20.01 micrograms/ml (range, 11.4 to 28.9 micrograms/ml) and remained stable for the duration of the procedure. In both groups perfusion pressure, urinary output, and body temperature did not seem to have any influence on these levels. It is concluded that the administration of one dose of cefazolin intramuscularly before operation results in an adequate and stable serum cefazolin level in patients undergoing cardiopulmonary bypass for up to three hours, possibly longer.

Adult↗
PubMed1979

Increased monocyte-mediated cytostasis of lymphoid cell lines in breast and lung cancer patients.

Peripheral blood mononuclear cells of most normal adults and patients with breast or lung cancer were found to inhibit [3H] thymidine uptake by lymphoid cell lines in a growth inhibition assay. At effector:target cell ratios between 5:1 and 20:1, lung cancer patients and breast cancer patients, when compared to normal individuals, demonstrated significantly greater inhibition of [3H] thymidine uptake by a human lymphoid cell line (F-265). The effector cells were adherent and were probably monocytes. Sephadex G-10 column passage or adherence to plastic removed most growth-inhibitory activity. Adherent cells recovered from plastic flasks (88-94% monocytes) were strongly growth-inhibitory. Lung cancer patients receiving BCG immunotherapy were found to have an apparently increased activity compared to patients not treated with BCG. The possible mediation of the growth inhibition by release of prostaglandins was suggested by the reduced cytostatic effects in the presence of indomethacin. Growth-inhibitory activity was not species-restricted, since human effector cells and also effector cells from tumor-bearing mice were reactive against the human target cell and against a murine lymphoma line (RBL-5). Natural killer (NK) cells did not appear to contribute appreciably to the observed cytostasis, since the levels of their activities did not correlate, and human NK cells are non-adherent and have little reactivity against F-265 or RBL-5. The inhibition of [3H]thymidine uptake by target cells was demonstrated to be a good reflection of actual inhibition of proliferation, since incubation of adherent cells from cancer patients with F-265 resulted in similar degrees of reduction in the number of target cells and in [3H] thymidine uptake.

Animals↗