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Biomedical subjects

R J Berry

Publications and source records attributed to R J Berry.

At least 19 recordsLinked to original sources
PubMed1992

The changing epidemiology of neural tube defects. United States, 1968-1989.

OBJECTIVE: To describe the recent trends and epidemiologic characteristics of neural tube defects in the United States. RESEARCH DESIGN: Ongoing surveillance data. SETTING: Two birth defect surveillance systems: the nationwide Birth Defects Monitoring Program and the Metropolitan Atlanta (Ga) Congenital Defects Program for 1970 through 1989 and 1968 through 1989, respectively. PARTICIPANTS: Between 1970 and 1989, using discharge diagnoses of approximately 1 million live-born and stillborn infants per year, the Birth Defects Monitoring Program identified 15,503 cases of spina bifida and anencephaly. Between 1968 and 1989, using discharge diagnoses and clinical records until age 1 year of 38,000 infants per year, the Metropolitan Atlanta Congenital Defects Program identified 800 cases of spina bifida and anencephaly. INTERVENTIONS: None. MEASUREMENTS/MAIN RESULTS: Nationwide, neural tube defect rates have declined from 1.3 per 1000 births in 1970 to 0.6 per 1000 births in 1989. In Atlanta, neural tube defect rates have declined from 2.0 per 1000 births in 1968 to 0.6 per 1000 births in 1989. Several changes in the epidemiologic characteristics of neural tube defects were observed: (1) the proportion of spina bifida cases has increased; (2) the proportion of neural tube defect cases compared with the proportion of other unrelated defects has increased; (3) the race ratio of whites to other races for isolated neural tube defect cases has declined in Atlanta; and (4) the rate of isolated neural tube defects in females has also decreased. CONCLUSIONS: The declining rates of neural tube defects can be partially explained by increased widespread prenatal diagnostic techniques, strongly suggesting the role of environmental factors in neural tube defects. In particular, the use of multivitamins and folic acid to prevent the occurrence of neural tube defects needs further evaluation. Nevertheless, the changing clinical and epidemiologic characteristics of cases over time points to the etiologic heterogeneity of these conditions.

Anencephaly↗
PubMed1992

Life history and bioeconomy of the house mouse.

1. More is known about the western European house mouse, Mus (musculus) domesticus than any other non-human mammal. If laboratory and field information is combined, an extremely valuable understanding of the species' bioeconomy could be obtained. 2. The seven stages of mouse life-history are surveyed (up to birth, nest life, sex life, social structure, population statics and stability, senescence, and death), and the interactions between the changing phenotype and the environment are described. 3. These interactions can be used to build up a model of the opportunities and compromises which result in the fitness of individual mice. It is not yet possible to quantify such a model, but this should in principle be achievable.

Animals↗
PubMed1979

A place for oncology in medical undergraduate teaching.

Cancer is a common disease, and it is argued that integrated teaching of the problems of the cancer patient deserves a place in the undergraduate medical curriculum. A model is presented which has now been used for 3 years and appears to be operating successfully at the Middlesex Hospital Medical School.

Curriculum↗
PubMed1978

Dare we count the cost of cancer chemotherapy?

During 1972-1976, when the incidence of cancer rose only slightly in the United Kingdom and the number of cancer patients seen at a large metropolitan teaching hospital and oncological centre remained largely unchanged, the use of cytotoxic drugs rose from 5.1% to 14% of the hospital's total drug budget. Most of the rise in cost can be ascribed to the increased use and increased unit cost of four effective but expensive drugs. Although the cost of drugs is but a small proportion of the cost of care of the cancer patient, it is argued that cytotoxic chemotherapy cannot offer a "cheap alternative" to surgery and radiotherapy. In a health service with cash spending limits the use of the more expensive cytotoxic drugs should be limited to the treatment of patients in whom "cure" or long-term ablation of disease is being attempted or to protocol studies in which their effectiveness is compared with that of other, possibly less expensive, drugs. Further studies are required of the use of the less expensive cytotoxic drugs in order to maximise their usefulness in the palliative treatment of advanced disease.

Antineoplastic Agents↗
PubMed1977

High energy fast neutrons from the Harwell variable energy cyclotron. I. Physical characteristics.

A high energy fast neutron beam potentially suitable for radiotherapy was built at the Harwell variable energy cyclotron. The beam line is described and results are given of physical measurements on the fast neutron beams produced by 42 MeV deuterons on thick (4 mm) and thin (2 mm) beryllium targets. With 20 muA beam current the entrance dose rate in a phantom 150 cm from the target was about 130 rad min-1 with the thick target and about 60 rad min-1 with the thin target. Therefore, it is possible to use both the thin target and the relatively large target-skin distance of 150 cm to improve depth dose for radiotherapy or radiobiology. With this arrangement the dose rate decreased to 50% at depths in the phantom of 11.3-15.4 cm, depending on the field size. The use of primarily hydrogenous materials for shielding and collimation provided beam edge definition similar to that of 60Co teletherapy units, and off-axis radiation levels of approximately 1% which compare favorably with 14 MeV deuteron-tritium generators. The copper backing of the thin target became highly radioactive and an alterative material may be preferable. Biologic characteristics of the beam are described in a companion paper.

Fast Neutrons↗
PubMed1976

Diagnostic x-rays in late pregnancy and in the neonate.

A survey has been carried out of current practice of radiology in late pregnancy and in neonates in the U.K. In major hospital centres, up to 34-8% of all pregnancies are still X-rayed, as well as up to 10% of neonates. It is suggested that criteria for X-ray examinations in late pregnancy and of the neonate need closer scrutiny.

Attitude of Health Personnel↗
PubMed1976

Skin response to X-irradiation in the guinea-pig.

Skin reaction to X-irradiation has been studied in the albino guinea-pig; early response in limited-field irradiations of the flank is comparable to that commonly seen in rodents, swine and man, and is dose-dependent with a dynamic range from mild erythema to moist desquamation. The peak early skin reaction is seen between 14 and 21 days after irradiation, and declines before 30 days except at the highest doses used. Fractionation of the X-ray dose at 24 hours results in a 'sparing' of about 340 rad. Permanent partial epilation is detectable at doses in excess of 1400 rad, and complete epilation at 1 year occurs in 50 per cent of irradiated fields at 1740 rad. Twenty-four hour two-dose fractionation results in a 'sparing' of about 500 rad for epilation. Palpable dermal 'fibrosis' is detectable at 3 months after irradiation in fields given more than 2070 rad, and at 1 year after irradiation in fields given more than 1800 rad; 50 per cent of fields showed palpable 'fibrosis' at 1 year at 1930 rad. Unlike domestic swine and man, skin fields in the guinea-pig showed no dimensional contraction after X-ray doses which produced gross early skin damage.

Animals↗
PubMed1976

A comparison for use in radiotherapy of neutron beams generated with 16 and 42 MeV deuterons on beryllium.

The physical and radiobiological properties of two neutron beams have been compared. The beams were generated by deuterons of 16 MeV at Hammersmith Hospital and 42 MeV at Harwell, in both cases falling on a Be/Cu target. The dose-rate and depth-dose characteristics at the higher energy were found to be superior to those at the lower energy. Collimation and shielding at the higher energy are facilitated by the greater degree of forward-peaking and by the fact that a higher dose-rate allows longer collimators to be used. Attenuation in iron was found to be similar at the two energies. The radiobiological properties of the two neutron beams are very similar. There is a difference of about 20 per cent in RBE for effects on mammalian tissues for doses between 300 and 2,000 rad of neutrons. The OER and the sparing effect of two large fractions are the same for the two beams.

Animals↗
PubMed1976

Change in oxygen enhancement ratio with depth in tissue-equivalent material for a collimated beam of fast neutrons.

Survival of reproductive capacity of murine leukaemia P-388 cells was assayed in vivo after the cells had been irradiated in vitro under aerobic or hypoxic conditions with collimated beams of X rays or 16 MeV D-Be fast neutrons at various depths in tissue-equivalent phantom material. The response to X-irradiation was the same in the absence of the phantom and at 8-7 cm depth. The response to fast neutrons under aerobic conditions was unchanged from 0 to 23 cm depth within the phantom. However, under hypoxic conditions, the dose-response curve for fast neutrons became significantly steeper with increasing depth in the phantom. The OER decreased from 2-0 in the absence of the phantom to 1-5 at 15 cm deep.

Animals↗