Primary chondrosarcoma of the lung.
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Adult↗
Biomedical subjects
M Kroll
Publications and source records attributed to M Kroll.
Poly(A) polymerase in quail oviduct. Changes during estrogen induction.
A nuclear poly(A) polymerase has been isolated from oviducts of immature quails. It could be purified 4300-fold. The enzyme depends specifically on ATP as substrate and requires Mg2+. The most effective primer for the enzyme is a polynucleotide, isolated from oviduct tissue. A poly(A) sequence to a maximum of 60 AMP residues is covalently linked per primer molecule. The poly(A)-rich product of the enzymatic reaction can be annealed to oligo(dT)-cellulose. The purest fraction does not contain any detectable poly(A)-degrading enzyme activity. Only very low activities of RNA polymerase are present. The poly(A polymerase activity in the assay with ATP is reduced by the ATP analogue, beta, lambda-ATP-methylene-diphosphonate. Both K-m and V are lowered. The ATP analogue is incorporated to a smaller extent into the poly(A) sequence, synthesized by the enzyme. Several other analogues of adenine, adenine nucleosides and adenine nucleotides are without effect on the enzymatic reaction. By these properties poly(A) polymerase can be distinguished from RNA polymerases form I and form II, isolated from the same tissue. Actinomycin D and alpha-amanitin failed to inhibit poly(A) polymerase activity. The activity of poly(A) polymerase has been determined during primary stimulation with the estrogen analogue diethylstilbestrol (daily injection for 5 days), after withdrawal of the hormone for 17 days and after secondary stimulation with the hormone analogue. The enzyme activity does not change during primary stimulation, withdrawal of the hormone or secondary stimulation. However the activity of a poly(A) degrading enzyme, localized in the nucleus, is reduced in oviducts from hormone-treated quails.
Adenine Nucleotides↗
Gram-negative endophthalmitis: Case report.
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Aged↗
Sodium-dependent efflux and exchange of GABA in synaptosomes.
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Amino Acids, Diamino↗
Acquired idiopathic nystagmus and oscillopsia.
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Chlorpromazine↗
Torque-velocity relationships of the knee extensor and flexor muscles in individuals sustaining injuries of the anterior cruciate ligament.
Muscle deficits in 58 patients with chronic anterior cruciate ligament (ACL) insufficiency were evaluated after completion of a 6 month rehabilitation program. Quadriceps and hamstring torques were measured on a modified Cybex II isokinetic dynamometer. Twenty-nine of our patients were tested just prior to undergoing ACL reconstruction, and patients who were continuing to tolerate their conditions served as controls. For the surgical group, significant quadriceps deficits (P less than 0.01) were found for all speeds and at both the 30 and 60 degrees positions. The nonsurgical group had significant deficits at the 30 degrees position at 180 degrees/sec, and at 60 degrees for the 0 degree/sec and 30 degrees/sec. However, in comparing the two groups no significant differences were noted. Regarding hamstring deficits in the surgical group, significant deficits were seen only at 30 degrees of flexion at 180 degrees/sec. The nonsurgical group had similar deficits. Of interest was the observation that the hamstring:quadriceps (H:Q) ratio was found to be both speed-position dependent. Overall, no correlation was found between the presence of strength deficits following a rehabilitation program and the need for surgery.
Adolescent↗
Managing the climacteric.
HRT taken for a sufficient duration may reduce the occurrence of osteoporosis and of cardiovascular disease by up to 50% and possibly also reduce incidence and lessen severity of Alzheimer's disease. Nevertheless, it is often only prescribed when women request it to relieve climacteric symptoms. Furthermore, many physicians prescribe it for only limited periods of time and few are willing to prescribe it to women in their sixties. As with any long-term prevention strategy, the uptake of HRT is much lower than the prescription rate, since the medication is often abandoned due to side effects or due to lack of motivation. But HRT is often abandoned also due to fear of cancer. While physicians may be aware of some beneficial effects of HRT, they often have no time to inform their patients of them. Alternatively, some of the beneficial effects such as cardioprotection or a reduced incidence of Alzheimer's may be less known. Likewise, HRT-related side effects or risks such as breast cancer or thromboembolic diseases should be discussed prior to HRT prescription. Women need to be informed about these potential risks, and this should be done by their physician. Surveys have shown that many women feel that they receive insufficient information from their physician. The quality of the relationship between physician and patient probably has a large influence on HRT acceptance, but very few studies have been conducted to assess specifically factors influencing the prescription and the continuation rate of HRT. Simple strategies may be among the most effective ones; these include listening to patients' fears, complaints and questions, and taking the time to answer them. The role of a practice nurse in such a setting may be also very important.
Attitude to Health↗
Osteoporosis management.
About 40% of women who reach the age of 50 are expected to suffer from osteoporosis during their remaining life. The morbidity associated with hip, spinal and wrist fractures, resulting from osteoporosis, and the mortality resulting from hip fractures justify the development of prevention strategies. Optimal management of osteoporosis consists of maximizing peak bone mass in early adulthood and preventing the rapid bone loss that occurs soon after the menopause. Peak bone mass will be reached in most women if adequate nutrition is taken and exercise is encouraged, while major risk factors are avoided. At the menopause, prescription of hormone replacement therapy (HRT) constitutes the primary prevention strategy. There are, however, questions that remain unanswered or debated. What is the optimal dose of HRT, when should it be started, and for how long should it be maintained? In women who do not, or may not, take HRT, and who have osteoporosis, alternative therapeutic options include diphosphonates (e.g., alendronate) and Selective Estrogen Receptor Modulators (such as raloxifene). Other treatments to restore bone strength in women with established disease may also reduce the risk of fractures. Some of them, such as calcitonin, may not be cost effective. Others have produced conflicting data (fluoride) and others are still under evaluation (PTH or strontium). In sunlight-deprived, vitamin D-deficient elderly nursing home residents, dietary supplementation of calcium and vitamin D has been shown to prevent bone loss and fractures. Strategies to avoid falls should also be encouraged for these patients.
Aged↗
The menopause in Europe.
Most women in developed countries will live a third of their lives after the menopause. Vasomotor symptoms (hot flushes, night sweats, irritability, sleep disturbances, mood swings), and urogenital complications (atrophic vaginal irritation and dryness, dyspareunia) occur frequently during this period of life, but their severity and duration may vary widely between individuals. The menopause also induces accelerated bone loss and is the principal risk factor for osteoporosis. Hormone replacement therapy (HRT; estrogen or estrogen plus progestogen) alleviates these symptoms and can be administered orally, transdermally, topically, intranasally, or as subcutaneous implants. HRT is also effective for prevention and treatment of postmenosausal osteoporosis throughout the time that it is used. It is not surprising that HRT use has increased substantially during the past decade. Nevertheless, there are still considerable variations in use between different countries within the European community. This presentation will analyze: the frequency of menopausal symptoms among women in different European countries and the factors that influence them; the frequency of other postmenopausal women's health issues in Europe; the use of HRT in Europe as well as the type of HRT and its evolution during the last decade; and possible reasons explaining heterogeneity between countries.
Aged↗
[Compliance with hormone replacement therapy].
Hormone Replacement Therapy (HRT) after menopause reduces climacteric symptoms and increases the quality of life. If correct dosage is used, bone loss can be prevented and fracture frequency reduced. Epidemiological studies also suggest a decreased cardio-vascular mortality among HRT users. A high proportion of post-menopausal women should therefore be treated using long-term therapy, but currently only a small proportion of women use HRT in Belgium, (around 14%). Further their compliance is particularly low. Fear of cancer and drug-related side effects, such as unaccepted bleeding are often mentioned causes of low compliance. Education of both physicians and patients, regarding HRT seems to be a crucial issue. The physician's attitude towards HRT is often reported as negative. Osteoporosis prevention and related bone mass measurements may have a favorable effect on compliance, but this is not well established. Establishing a confidential relationship with patients and the involvement of nursing counseling are strategies which may improve compliance. The use of easy-to-take medications supported by calendar blisters or reminders, may facilitate chronic use of medication. Future research needs to investigate the physician's and the patient's decision-making process.
Aged↗
Overview of the clinical usefulness of bone mineral measurements in the prevention of postmenopausal osteoporosis.
Bone mass measurements might be useful in two ways in prevention of postmenopausal osteoporosis: the decision to start HRT, or other therapy, could be based on such measurements; and, possibly, compliance to treatment would be enhanced. Bone density measurement appears to have sufficient predictive value for osteoporotic fracture, especially when density is measured by dual-energy X-ray absorptiometry. However, choice of skeletal site for the measurement cannot be made with certainty, although a vertebral site may be best early in menopause; and in women with osteophytes or scoliosis, and with older women, the femur or wrist may be preferred. With respect to enhancement of patients' compliance to HRT, as well as clinicians' willingness to prescribe treatment, it has not yet been clearly shown that bone mass measurements have a significant effect. This topic involves economic efficiency and should be evaluated by considerations of economics weighted against medical efficacy.
Adult↗
Osteoporosis prevention with sex hormone replacement therapy.
It was suggested as long ago as 1941 that there might be a connection between the menopause and osteoporosis. Since then, abundant data have confirmed that hypothesis as well as showing that such osteoporosis may be prevented by estrogen supplementation (ERT--estrogen replacement therapy). In estrogen deficiency, increased bone resorption takes place in the process of bone remodeling, leading to bone loss. The bone loss occurs universally but to the greatest extent at sites rich in trabecular bone. There are uncertainties concerning extent of bone loss at various sites at different ages, effect of ERT at varying sites and different ages, degree of fracture prevention, and relationship between duration of therapy and fracture risk. That optimal fracture risk is not being attained now on a population basis is due to apparently low acceptance of ERT by patients and lack of strenuous effort in that direction by physicians.
Age Factors↗
Principal cancers among women: breast, lung and colorectal.
The major variations in the pattern and level of cancer throughout the world reflect for the most part differences in the environment. It is generally agreed that carcinogenesis may arise as a result of chemical, physical, biologic, and genetic insults to cells. In addition, specific external factors may initiate and/or support malignant transformation, such as smoking, occupational and environmental chemicals, radiation, dietary factors, and specific viruses. Furthermore, endogenous compounds, such as steroid sex hormones, may be promoters for carcinogenesis of hormone-dependent tissue. Although some cancers seem to be related to inherited traits, research generally does not support the notion of group or inherited differences in cancer statistics. The leading causes of cancer death in females in 1991 in the United states were lung cancer (52,068), breast cancer (43,583), and colorectal cancer (29,017). According to the American Cancer Society, this year 182,000 women will be diagnosed with breast cancer, 73,900 with lung cancer, and 66,000 with colorectal cancer. Even with our knowledge about the influence of life style and environmental causes of cancer, little progress has been made. In breast cancer, only 25 to 30% can be attributed to known risk factors. Lung cancer in females, on the other hand, once a rare disease, turns out to be the leading cause of cancer death among women in industrialized countries, mostly due to smoking.
Breast Neoplasms↗
The brittle bone: how to save women from osteoporosis.
For a woman, the risk of suffering an osteoporotic fracture during her lifetime is higher than the combined risk of breast, endometrial, and ovarian cancer. It is important to reduce the number of osteoporosis-related fractures. Therefore, it is necessary to emphasize various interventions and attitudes which will decrease both the risk of falling and that of breaking bones. Strategies should be followed to reach adulthood with an optimal bone mass through improved diet and exercise during childhood. Programs that identify women with the lowest bone mass at the time of menopause may be useful, since prophylactic measures against osteoporosis such as hormone replacement therapy (HRT) can be offered to them. Identification of women at risk can be achieved through bone densitometry; a decrease of each standard deviation of bone mineral mass below mean values predicts a doubling of the fracture risk. Some data suggest that physicians are more willing to prescribe HRT specifically to women with the lowest bone mass, and that the latter are more likely to stay on therapy for longer periods of time. The decision to use HRT should be taken by the patient after proper information of all benefits (diminished climacteric symptoms, decrease of cardiovascular risk) and potential risks (possible enhanced breast cancer risk, appearance of side effect). In women who do not want to take HRT, or for whom contraindications exist, alternative medications, such as calcium, vitamin D and biphosphonates can be considered, depending on fracture risk. For older and institutionalized women, programs should be developed to decrease the risk of falling. Likewise, it may be possible to reduce the consequences of a fall, for instance by promoting the development of energy-absorbing hip pads, which reduce fracture risk.
Bone Density↗