An epidemiologic survey of senile cataract in China

This paper is based on data obtained in blindness screening in 7 rural areas throughout China and presented at the Second National Conference of the Chinese Ophthalmologic Society in 1979. This comparative study of the incidence of senile cataract in relation to geographic and meteorologic factors, with special reference to solar radiation, indicates that cataract incidence increases with decrease in latitude or increase in altitude due to increased solar radiation. Zedang in Tibet, with the highest altitude and low latitude (29 degrees N) has the highest incidence (1.32%) of the areas surveyed, followed by Aleitai 0.25% and Zhongshan (0.23%), whereas the incidences in lowland areas are between 0.12 and 0.14%, the lowest surveyed being in Zhongmou (0.066%). The differences in cataract incidence are apparently associated with solar radiation. Yu and coworkers in their research demonstrated the evidence for the solar UV-induced lowering of sulfhydryl level in the Tibet human lens nucleus. Therefore, these findings furnish some evidence supporting the theory that sunlight enhances cataract formation.

Models and assumptions underlying genetic risk assessment

Various methods employed for estimating the genetic risks of radiation are reviewed. With the doubling-dose method, genetic damage is expressed as an increase in cases of known genetic disease. The actual doubling dose is based on figures obtained with the mouse. There have been no recent data on induced mutation frequencies. Recent results suggest that the prevalence figure for multifactorial disease may be at least one order of magnitude higher than before. Various assumptions underlying the doubling-dose concept are discussed in the light of recent findings on: (1) spontaneous mutations resulting from insertion elements, and (2) the comparability between spontaneous and induced mutations. The so-called direct method makes use of figures for induction of dominant mutations affecting the skeleton and the lens of the eye in the mouse, and of translocation induction in monkeys. Induction rates are converted to overall rates of induced dominant effects in man by applying certain assumptions. The proportionality between dose and effect is the basis for all genetic risk assessments. The possible significance of data on human lymphocytes indicating a threshold below 4 rad and the induction of repair enzymes by low radiation doses is discussed. The parallelogram approach is based on the principle that estimates can be obtained on the amount of genetic damage that cannot always be assessed directly. Thus mutations in mouse germ cells can be predicted by using mutation frequencies in cultured mammalian cells and O6-ethylguanine adducts. Measurement of haemoglobin mutations in human and mouse erythrocytes, and of HPRT-deficient mutations in lymphocytes of man and mouse should make more precise estimates of mutation frequencies in human germ cells possible. The development of a database on mutations in somatic cells of the mouse, their induction frequencies and molecular nature are considered an important priority. Used in combination with mouse germ-cell mutation frequencies, they should enable more precise risk estimates on the basis of mutations in somatic cells of man.

Interference in pacemakers

We attempt here to outline the different sources of interference and the methods of interference detection and protection with their advantages and disadvantages. A proposal is made as to how a better interference suppression could be established. A comparison of 16 pacemakers from ten manufacturers tested with different interference sources revealed a great variety, which does not allow one to generalize the problem of interference. As an example, an electric steel furnace with its magnetic field is described and how its influence on pacemakers can be estimated. Rules are given as to how pacemaker patients may be treated by electrotherapy. A test procedure for characterizing the specific interference behavior is proposed.

Effects of physical forces on the reproductive cycle. Council on Scientific Affairs

The Council on Scientific Affairs is aware that physicians, as well as the public in general, have expressed increasing concerns regarding the possible adverse effects of various physical forces on the reproductive organs. Various channels of public communication report anecdotal episodes of suspected cause-and-effect relationships between various physical elements in the environment and harmful effects on reproduction. Many of these episodes have not been substantiated by acceptable scientific research. However, some reports have appeared in the scientific literature that do document adverse reproductive effects on humans and animals at certain levels of some physical forces. At levels above 3,636 m (12,000 ft), adverse reproductive effects have been observed in men and women, in the conceptus, and in certain species of animals. Hyperthermia in excess of 40 degrees C may affect the man and the conceptus, as well as the reproductive capacity of certain animals. However, adverse effects of hypothermia have been observed only in animals. Ionizing radiation can cause injury to the man, woman, and conceptus and to animals, depending on dose and duration of exposure. There have been no well-documented injurious effects to the human reproductive organs resulting from radiofrequency-microwave radiation, but there have been some reports in animals that attributed untoward reproductive limitations to thermal effects. To date, there have been no reports in the scientific literature to implicate electronic and magnetic fields, gravity and acceleration, noise, optical radiation (UV, visible, infrared, and lasers), ultrasound, or vibration as having harmful effects on reproduction in either humans or animals. There is need for more well-designed and controlled studies to be performed in all of these areas of exposure at maximum-tolerated levels to physical force before it can be determined with certainty that no ill effects will accrue to the reproductive cycle, especially in assessing harmful effects from low-level exposure during long periods of time.

Teratogenesis: a review of the basic principles with a discussion of selected agents: Part III

Before a woman realizes she is pregnant, a large amount of development has occurred in the embryo. If she consumes a drug during her pregnancy, the possibility exists that the drug could harm the fetus. The most important variable is timing, with the fetus showing the highest degree of susceptibility during the first trimester of gestation.

This article presents data on the relative time a pregnancy test becomes positive as compared to fetal development; passage of drugs across the placenta; placental and fetal drug metabolism; and the availability of teratogenic information to health professionals. Teratogenic effects of specific substances or classes of substances are discussed, including alcohol, analgesics, antibiotics, anticoagulants, anticonvulsants, antithyroid/thyroid drugs, various environmental agents, and paternal drug exposure.

Medical treatment of the infertile male

In summary, the effective treatment of certain disorders of male infertility is possible. As in all areas of medicine, the more specific the diagnosis, the more specific the treatment, and, as expected, the greater the success of treatment. Much of the confusion regarding the efficacy of the medical treatment of infertility has been generated by the use of empiric treatment modalities without thorough diagnostic evaluation. Further advances in knowledge pertaining to the mechanism of infertility should increase the precision of our forms of treatment, thus producing increased rates of success.

Radiation hazard to operating room personnel during operative cholangiography

During operative cholangiography, the surgeon and other operating room personnel are exposed to scattered radiation and its potential hazards. It was determined that a surgeon standing at the side of the patient during cholangiographic filming would receive 3.2 mR per film. Exposure would be only 0.5 mR per film if the surgeon stepped back 75 cm (2.5 ft) from the patient. This simple measure would reduce the monthly exposure of a surgeon who performs four cholangiograms per week from approximately 205 to 32 mR. The use of the new electronic video-disc recording systems and lead aprons can substantially reduce the amount of radiation exposure related to fluoroscopy. The prudent surgeon, recalling that no level of radiation may be totally safe, should use techniques that provide maximal protection for himself and all operating room personnel during performance of operative cholangiography.

Details of technique and results of staging laparotomy in the diagnosis of Hodgkin's disease

The operative procedure for staging laparotomy in Hodgkin's disease is described in detail. Of 18 patients undergoing this procedure, staging laparotomy changed the stage of disease and subsequent therapy in 38%. Complications of the operation were minor, occurring in only two patients. Abnormal lymphangiography and splenomegaly proved unreliable clinical diagnostic findings. Most disturbing was the 100% incidence of amenorrhea in the women receiving pelvic irradiation following oophoropexy.

Bone sarcomas: etiology and immunology

The etiology of skeletal sarcomas is found in induced by viruses in man (as they are in exogenous agents (irradiation, oncornavirus) acting in a peculiar setting of host factors. Patients with skeletal sarcomas react immunologically to autologous and allogeneic sarcoma cells, but reactors can be found among the healthy persons with or without exposure to patients with sarcomas. Various modalities of immunotherapy are available to increase the patient's immune reactivities in general or to sarcoma cells in particular, but immunotherapy of skeletal sarcomas has not yet brought about clear-cut and substantial benefits in addition to or beyond the results of conventional treatment.