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Biomedical subjects

R H Henderson

Publications and source records attributed to R H Henderson.

At least 19 recordsLinked to original sources
PubMed1992

Survival results in adult patients treated for medulloblastoma.

The records of all 27 adult patients (age, greater than or equal to 16 years) diagnosed with cerebellar medulloblastoma between 1968 and 1986 were reviewed. Twenty-four patients (89%) were treated with postoperative megavoltage irradiation. Twenty of these patients underwent craniospinal irradiation. Sixteen patients received greater than 5000 cGy to the posterior fossa (range, 2340 to 6600 cGy; median, 5490 cGy). Forty-eight percent of patients also received adjuvant chemotherapy. A 5-year and 10-year actuarial survival rate of 48% was achieved. The use of adjuvant chemotherapy did not improve survival in this series. All relapses occurred within 35 months of diagnosis (median time to relapse, 23.5 months), except one patient who had a recurrence in the posterior fossa at 140 months. The posterior fossa was the most common site of treatment failure and represented 50% of all initial relapses. All survivors had no sequelae, except one in whom leukoencephalopathy developed after craniospinal irradiation and intrathecal methotrexate administration. The survival results obtained in this series compare favorably with other reported modern adult medulloblastoma series.

Adolescent↗
PubMed1991

Principles of measles control.

WHO's Expanded Programme on Immunization has significantly helped to reduce global morbidity and mortality from measles. Recently, some African countries with high vaccine coverage levels have reported measles outbreaks in children above the current target age group for immunization. Outbreaks such as these are to be expected, unless close to 100% of the population are immunized with a vaccine which is 100% effective. Success of an immunization programme requires identification of the distribution and ages of susceptible children and reduction of their concentration throughout the community. Priority should be given to urban and densely populated rural areas. In large urban areas, high coverage of infants must be achieved soon after the age at which they lose their maternal antibodies and become susceptible. This will be facilitated by the introduction of high-dose measles vaccines which can be given at 6 months of age. Where measles incidence is increasing among children aged over 2 years, immunization of older children may be considered during contacts with the health care system, or at primary school entry, if this does not divert resources from immunization of younger children. Health workers should be informed of the predicted changes in measles epidemiology following immunization. The collection, analysis and use of data on measles (vaccine coverage, morbidity and mortality) should be improved at all levels of the health care system in order to monitor the immunization programme's overall impact, identify pockets of low coverage, and allow early detection of and response to measles outbreaks.

Africa↗
PubMed1990

Vaccinations in the health strategies of developing countries.

The initiative established by the World Health Organization in 1974 under the title of the Expanded Programme on Immunization (EPI) has resulted in immunization programmes being strengthened in developing countries so that they now cover 66% of children reaching their first birthday with a dose of DPT or polio vaccines. Immunization programmes are currently preventing over 2 million deaths among children in developing countries from measles, neonatal tetanus and whooping cough. Future challenges for the EPI include: raising and sustaining immunization coverage; controlling the target diseases, with specific focus on the control of measles, the elimination of neonatal tetanus and the eradication of poliomyelitis; introducing new or improved vaccines; promoting other primary health care practices; and research and development. Immunization will become an increasing priority for developing and industrialized countries alike as an increasing array of vaccines become available for public health use. Further research to simplify and reduce the costs of vaccine production and administration and to better understand the factors contributing to the acceptability of immunization services is needed as a complement to research to develop additional vaccines.

Developing Countries↗
PubMed1990

Worldwide control of disease through immunization. Progress and prospects.

In summary, tremendous advances have been made over the past 15 years toward the development of effective national immunization programs throughout the world. Immunization levels among children in the developing world have risen dramatically, and in some instances, now equal or exceed levels in industrialized nations. There is no room for complacency, however, because millions of children remain incompletely immunized and many die each year from measles, pertussis, and neonatal tetanus. Immunization activities need to be intensified, accelerated, and sustained within the context of the primary health care system. Expansion of immunization programs to include additional vaccines and other simple health interventions will yield further benefits in the years ahead.

BCG Vaccine↗
PubMed1989

Differences in secretion of prostacyclin by venous and arterial endothelial cells grown in vitro in a static versus a mechanically active environment.

The objective of this study was to compare the effect of cyclic tension on prostacyclin secretion by venous and arterial endothelial cells. Early passage endothelial cells from bovine aortas and venae cavae were subjected to cyclic deformation (up to 17% elongation and 60 cycles/min). On posttreatment days 3 and 5 a radioimmunoassay was used to assess supernatant fluids from the endothelial cells for prostacyclin activity. The results indicate that in vitro (1) under static or control conditions, venous endothelial cells secrete significantly more prostacyclin (an increase of 1.5- and 4.8-fold on days 3 and 5, respectively) than do arterial endothelial cells isolated from the same animal and (2) prostacyclin secretion by mechanically deformed venous and arterial endothelial cells was significantly less than static control cultures on days 3 and 5. However, prostaglandin I2 secretion remained at higher levels in cyclically deformed venous endothelial cells than in cyclically deformed arterial endothelial cells. These data suggest that endothelial cells from the vena cava have a greater capacity for prostacyclin secretion than have their aortic counterparts. If these observations are maintained in vivo, greater prostacyclin secretion by venous endothelial cells could represent a homeostatic mechanism aimed at reducing thrombus formation in low-velocity areas of the vasculature.

Arteries↗
PubMed1988

Expanded programme on immunization.

The Expanded Programme on Immunization (EPI) was established in 1974 to develop and expand immunization programmes throughout the world. In 1977, the goal was set to make immunization against diphtheria, pertussis, tetanus, poliomyelitis, measles and tuberculosis available to every child in the world by 1990. Problems encountered by the Programme have included: lack of public and governmental awareness of the scope and seriousness of the target diseases; ineffective programme management; inadequate equipment and skills for vaccine storage and handling; and insufficient means for monitoring programme impact as reflected by increasing immunization coverage levels and decreasing incidence of the target diseases. When the EPI was initiated in 1974, fewer than 5% of children in developing countries were receiving a third dose of DPT and poliomyelitis vaccines in their first year of life. These coverage levels have now surpassed 50% in developing countries, and millions of cases of the target disease have been prevented. Over 700,000 measles deaths were prevented by immunization in developing countries in 1987, and an increasing number of neonatal tetanus deaths is now being prevented by maternal immunization and improved childbirth conditions. Poliomyelitis immunization efforts have been so successful that the Pan American Health Organization is leading a drive to eradicate poliomyelitis from the Americas by 1990. The successes of the Programme represent a major public health achievement, but much remains to be done.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗