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Biomedical subjects

J B Anderson

Publications and source records attributed to J B Anderson.

At least 91 records · Page 5Linked to original sources
PubMed1978

Radiological determination of changes in bone mineral content.

It is possible to obtain reliable data of changes in bone mineral content using simple radiographic techniques. Methods available include morphometry and densitometry. Of these morphometry of the third metacarpal is most accurate in our hands and cortical width is the most reliable of such morphometric data. Densitometry produces more variable results and shows no advantage over straight measurement of cortical width. The only acceptable alternative method of obtaining information about bone status is photon absorptiometry. Results of these methods are shown in a trial of oestrogen therapy for the prevention of post-menopausal osteoporosis. The data suggest that oestrogens prevent post menopausal bone loss when this is estimated by measurement of cortical width or photonabsorptiometry.

Absorptiometry, Photon↗
PubMed1977

Comparative effects of hycanthone in Schistosoma mansoni and Schistosoma japonicum.

After in vitro hycanthone treatment followed by a 20-hour incubation in drug-free medium, Schistosoma mansoni were still resistant to labeling by a fluorescent analog of acetylcholine. S. japonicum, in contrast with the hycanthone sensitive species, showed prompt reversal of the blocking effects of hycanthone on fluorescent labeling. This finding suggests that differences in the reversibility of hycanthone may correlate with the usefulness of the drug in the therapy of schistosome infections by different species of parasites. Scanning electron microscopy has been used to demonstrate that hycanthone treatment causes degeneration of the integument of S. mansoni, but not S. japonicum, over a period of few days after in vivo exposure to hycanthone. The mechanism by which hycanthone causes this effect is not known.

Acetylcholine↗
PubMed1976

Long-term prevention of postmenopausal osteoporosis by oestrogen. Evidence for an increased bone mass after delayed onset of oestrogen treatment.

Treatment of 63 oophorectomised women with oestrogen for five years prevented the reduction in bone mineral content observed in 57 women treated with a placebo preparation. When onset of therapy was delayed for three to six years there was a highly significant increase in bone mineral content mainly during the first three years of treatment. During the next two years there was no further increase in bone mineral, while the placebo-treated groups continued to lose bone at about 1% per annum. In association with the changes in bone mass, the expected biochemical effects of oestrogen therapy also persisted for at least three years, and were compatible with a prolonged increase in parathyroid activity but a reduction in bone turnover.

Adult↗
PubMed1976

Tissue distribution of (14C) methyl mercury in the lobster, Homarus americanus.

[14C] Methyl mercury was administered by three different routes: intravascular (iv) injection, ingestion, and absorption from the ambient water. After iv administration (0.1 mg/kg) [14C] methyl mercury was rapidly removed from the plasma, followed by slow loss from the hepatopancreas and a strikingly persistent increase in the amount of radioactivity in the tail muscle. Most (80-90%) of the radioactivity in the hepatopancreas was shown by TLC methods to be the parent compound, and approximately 10% of this persisted for 6 days after injection. The half-life in this organ was found to be 21 days. One month after iv treatment with methyl mercury, the only organs that contained more than 0.1 ppm of this xenobiotic were egg masses, male gonads, heart, brain, intestine, and tail muscle. The half-lives for disappearance from sexual organs were greater than 1 month. After ingestion of [14C] methyl mercury (0.1 mg/kg) in food the hepatopancreas contained most of the administered dose at 6 days (68%), while the stomach (10%), tail muscle (8%), and carcass (15%) contained less. A unique distribution pattern emerged 6 days after exposure to [14C] methyl mercury-containing ambient water (0.1 ppm). The tail muscle contained most (50%) of the absorbed dose, whereas the hepatopancreas and carcass contained only 23 and 10%, respectively. In view of the small molecular size and high lipid solubility of methyl mercury and the lipophilic properties of the chitin-protein exoskeleton of the lobster, it is likely that significant uptake directly from the water as well as storage of absorbed methyl mercury occurred in the tail region. Residue analysis on untreated lobsters indicated that the egg masses contained the largest amount of methyl mercury (0.1 ppm). The hepatopancreas and carcass (muscle) levels were less than 0.05 ppm.

Absorption↗
PubMed1976

Excretion of phenol red and its glucuronide in the dogfish shark.

1. The biliary and urinary excretion of phenol red and its glucuronide was measured in dogfish sharks, Squalus acanthias, in both intact animals and animals with biliary fistula. 2. Phenol red is extensively metabolized to its glucuronide by the dogfish shark and both forms of the compound are actively transported into bile and urine. 3. Both compounds are transferred from plasma to urine and bile against a large concentration gradient; the transfer process is saturable most easily in the renal compartment but also in the hepatic compartment; and both excretion routes for the free drug and the glucuronide are inhibited by probenecid. 4. There were no significant differences in the 48 h biliary excretion of total (free + glucuronide) phenol red, but the urine or intact fish contained two-fold more total drug than did animals with fistulae.

Animals↗
PubMed1976

Prevention of bone loss following oophorectomy in premenopausal women: a retrospective assessment of the effects of oophorectomy and a prospective controlled trial of the effects of mestranol therapy.

Prospective studies of bone mass in women following oophorectomy for benign conditions were done by the double-blind technique. Skeletal response to treatment was measured by photon absorption densitometry. Untreated patients were found to lose bone mass rapidly during the first two years after oophorectomy. When estrogen replacement was started within two months of oophorectomy, it was found to be effective in preventing subsequent bone tissue loss. Three years following oophorectomy, untreated women who had already lost bone tissue, and who were then started on estrogen replacement, showed a highly significant increase in their bone mass. The women in whom this treatment was delayed for six years did not respond. No untoward effects were noted in these women, perhaps, in part, because they had undergone hysterectomy. Long-term effects of this treatment are now being evaluated.

Adult↗
PubMed1975

Etiology of nongonococcal urethritis.

Chlamydia trachomatis was isolated from the urethra from 48 (42 per cent) of 113 men with non-gonococcal urethritis (NGU), four (7 per cent) of 58 without overt urethritis, and 13 (19 per cent) of 69 with gonorrhea. Postgonococcal urethritis (PGU) developed in 11 of 11 men who had C. trum antibody to C. trachomatisis developed. The immunotype specificity of chlamydial antibody corresponded to the immunotype isolated. Among culture-negative patients. chlamydial antibody prevalence correlated with the number of past sex partners and with previous NGU. Herpesvirus hominis, cytomegalovirus, T-mycoplasma, Mycoplasma hominis, other bacteria, and Trichomonas vaginalis were not implicated in NGU or PGU. Thus, the cause of chlamydia-negative NGU and PGU remains obscure. Endocervical chlamydia were found in sex partners of 15 of 22 NGU patients with and two of 24 without urethral chlamydial infection (p smaller than 0.001). Tetracycline treatment of both sex partners appears advisable.

Antibodies, Bacterial↗
PubMed1975

The relation between sub-capital fracture of the femur and mineral content of the right third metacarpal.

Positive correlation between the mineral content of the mid site of right third metacarpal and neck of femur has been established using the psi-ray absorption technique described by Shimmins et al. (1972b) to make measurements on excised human bones. An X-ray method (Anderson, Shimmins and Smith, 1966; Shimmins et al. 1972a) was used to measure the mineral content of the right third metacarpal in 101 female and 22 male patients with subcapital fracture of the ferum. When their metacarpal "whole bone densities" were compared with those of control subjects of the same age and sex, they were found to have significantly lower (P smaller than (0.025) average values. However, groups of patients defined according to Garden's classification of severity of fracture could not be distinguished one from the other on the basis of metacarpal whole bone density measurement.

Adult↗
PubMed1975

Bone loss in patients with rheumatoid arthritis.

Both male and female patients with rheumatoid arthritis show a significant bone loss in the femur, compared with the loss of bone seen in normal subjects with increasing age. A very similar pattern is seen in corticosteroid treated patients with rheumatoid arthritis. There is no evidence to suggest that the corticosteroid therapy has caused a greater loss of bone from the femur than would have occurred as a result of the rheumatoid arthritis alone. There was a statistically significant relation between the duration of the rheumatoid arthritis and femoral bone lo-s in women over the age of 45 years, whether or not they had been given steroid therapy in both male and female patients over 45 years of age, but again it appears unlikely that corticosteroid therapy had contributed significantly to the femoral bone loss. The Metacarpal and Femoral Indices of the patients were significantly related in both male and female groups.

Adrenal Cortex Hormones↗
PubMed1973

Osteoporosis after oophorectomy for non-malignant disease in premenopausal women.

The role of oophorectomy in the development of osteoporosis was assessed retrospectively in 258 women who had been hysterectomized premenopausally for non-malignant disease. Bone density was assessed using the radiographic density of the third metacarpal. Oophorectomy before the age of 45 years was found to be associated with a significantly increased prevalence of osteoporosis within three to six years of operation. The bone density of women oophorectomized after the age of 45 years was indistinguishable three to six years after operation from that found in healthy women with intact ovaries. These findings confirm the major part played by loss of ovarian function in the development of postmenopausal osteoporosis.

Absorptiometry, Photon↗