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Biomedical subjects

A M Ramirez

Publications and source records attributed to A M Ramirez.

10 recordsLinked to original sources
PubMed1991

Peripheral-type benzodiazepines inhibit proliferation of astrocytes in culture.

Peripheral-type benzodiazepine (BZD) receptors have been identified in brain and are predominantly localized to astrocytes. To determine their potential role in controlling astroglial proliferation, DNA synthesis, growth curves and mitotic index were investigated in primary astrocyte cultures which had been exposed to Ro5-4864 (a peripheral-type BZD ligand) and PK11195 (a peripheral-type BZD receptor antagonist). There was a dose-dependent inhibition of mitosis when two-week-old cells in culture were exposed to 50 nM, 500 nM, 1 microM and 10 microM Ro5-4864 for 24 h. Exposure of 5-, 8-, 12- and 15-day-old cultures to Ro5-4864 and PK11195 for 24 h did not affect growth rate and DNA synthesis; however, continuous exposure to 10 microM Ro5-4864 caused a persistent inhibition of cell growth and [3H]thymidine incorporation (P less than 0.05) while nanomolar concentrations did not cause any significant change. Concurrent administration of Ro5-4864 with PK11195 resulted in a partial reversal of Ro5-4864-induced inhibition in DNA synthesis and mitosis. These results indicate that peripheral-type BZDs are capable of inhibiting proliferation of astrocytes in culture.

Animals↗
PubMed1989

Morbidity from acquired cytomegalovirus infection in a neonatal intensive care unit.

In a prospective study of transfused neonates, 32 of 262 infants were viruric at greater than 20 days of life. Of 212 neonates whose early status was known, postnatally acquired infection was proven in 21, two of whom were seronegative at birth and were thought to have transfusion-acquired cytomegalovirus (CMV). Maternal transmission of CMV is important in this population as there was 91% seropositivity for CMV at birth among the 21 babies who acquired CMV compared with 55% positivity among 150 babies who did not shed CMV (P less than 0.01). Significantly increased morbidity (increased length of stay in hospital, increased use of antibiotics, and longer duration of antibiotic administration) was found in babies with acquired CMV compared with matched controls who did not become viruric. Significant morbidity and mortality was not restricted to the two seronegative babies with transfusion-acquired CMV. The cost of providing CMV antibody negative blood for this neonatal unit would be less than the cost of providing the extended hospital care needed by the two babies with transfusion-acquired CMV found during this 3 year study.

Cytomegalovirus↗
PubMed1987

Posttransfusion hepatitis: a persistent problem.

Between 1977-84 the reported frequency of clinically evident posttransfusion hepatitis has halved both nationally and in the Auckland region. This is mainly due to a decrease in the frequency of posttransfusion hepatitis B coincident with widespread introduction of sensitive screening tests for HBsAg. About half the cases of transfusion induced hepatitis are now classified as non A non B hepatitis. A further fall in the reported frequency of posttransfusion hepatitis occurred in 1985-86. Possible strategies to further reduce the low frequency of posttransfusion hepatitis in New Zealand are discussed. Although the problem of clinical posttransfusion hepatitis B or non B appears small, the need to report all such cases and to utilise blood and blood products with care is emphasised.

Hepatitis B↗
PubMed1987

Hepatitis delta virus infection: a recently imported disease in New Zealand.

In a study of 565 hepatitis B antigen (HBsAg) positive persons from the Auckland region, antibody to the hepatitis delta virus was detected in 38. The largest number were in Samoans (61%) although the infection was present in some other Pacific Islanders. Among HBsAg positive healthy blood donors, antenatal patients and acute hepatitis patients between 3.8 and 4.8% were anti-delta positive; while 28% of chronic hepatitis patients were positive suggesting an association between this disease and delta infection. Some positive results were also found in sera from intravenous drug addicts. By contrast, anti-delta was uncommon in New Zealand born Maoris or Europeans. Delta infection can be detected in some Pacific Islanders, some European immigrants as well as intravenous drug addicts and has the potential to spread in an epidemic form to HBsAg carriers in the general community. Widespread vaccination against hepatitis B is recommended to eventually reduce the number of HBsAg carriers in New Zealand.

Acute Disease↗
PubMed1986

Intradermal, low dose, short course hepatitis B vaccination.

Seventy-five of 88 (85.2%) vaccinees seroconverted at three months after three 2 micrograms doses of a plasma-derived hepatitis B vaccine had been given intradermally one month apart. Vaccinees under 30 years of age had a significantly better seroconversion rate (88.8%) than older subjects (50%) as measured at three months. Forty-three of 47 (91%) vaccinees who were bled one year post vaccination had antibody levels in excess of 10 IU/1. This study indicates that short course, low dose, intradermal vaccination with plasma-derived hepatitis B vaccine may be a viable and cheap regimen for inducing immunity against hepatitis B in younger subjects.

Administration, Cutaneous↗
PubMed1977

Percutaneous fixation of supracondylar fractures of the humerus in children.

Of 1,118 supracondylar fractures of the humerus in children treated over a six-year period, 189 are described with a follow-up of more than two years. These patients were treated with closed reduction and percutaneous fixation of the fragments with two wires. Eighty-five per cent of the final results were satisfactory.

Child↗