Biomedical subjects
Publications and source records attributed to J C Holmes.
In 1980 Osteonics marketed their universal head replacement (UHR) as a universal head to fit 32 mm heads. The authors present four cases of ring disassociation in the Osteonics UHR when combined with Howmedica femoral heads.
Data on costs associated with episodes of disease and disease prevention, including expenditures for veterinary services, were collected from 57 California beef cow-calf herds during 1988-1989 as part of the National Animal Health Monitoring System. Mean cost associated with episodes of disease was $33.90/cow-year, with $0.78 and $1.37/cow-year being spent for veterinary services and drugs, respectively. The highest cost for veterinary services related to episodes of disease were for dystocia, lameness, and ocular carcinoma. For disease prevention, mean expenditures for veterinary services were $1.67/cow-year, nearly all of which was spent on prevention of reproductive tract conditions. Preventive expenditures for veterinary services related to female infertility (pregnancy examination), vaccination against brucellosis and male infertility (breeding soundness examination) were $0.72, $0.39, and $0.22/cow-year, respectively. Many costs associated with episodes of disease and disease prevention were similar to those reported from Colorado National Animal Health Monitoring System beef herds.
Golden Syrian hamsters fed a cholesterol-free diet containing 25% casein had higher plasma total triglyceride and cholesterol levels and VLDL + LDL cholesterol levels than animals fed a 25% soybean protein diet. Hamsters fed the cholesterol-free casein diet also had higher HDL cholesterol levels than animals fed the soybean protein diet, but these differences were not statistically significant. Addition of cholesterol to the diets caused even greater mean differences between the animals fed different types of protein, but the increased inter-animal variability of response to the added cholesterol resulted in less statistically significant differences. Although less responsive than the nonhybrid Golden Syrian hamsters, hybrid F1B hamsters showed similar effects of dietary casein vs. soybean protein on plasma lipids. These results indicate that the hamster may be a useful model to examine the effect of different types of protein and the interaction with dietary cholesterol on various plasma lipids and lipoproteins.
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Twenty-nine California dairy herds were studied over a 12-month period from 1988 to 1989 as part of the National Animal Health Monitoring System. Monthly interviews administered to dairy producers were used to measure the costs of all health-related expenditures and disease incidence in these herds. Of the total $1,523,558 reported, $1,355,467 (89%) was attributed to cost of disease events and $168,091 (11%) to cost of disease prevention. Most (78%) of the cost of disease events was attributable to death and culling losses. Veterinary services accounted for only $54,099 (4%) of total costs, 64% of which was used for disease prevention, compared with 36% for disease treatment. Udder disease was the most costly category of diseases reported at an average of $49.85/head at risk annually, followed by reproductive problems at $38.05. Through the use of sampling strategies less biased than those used in other surveys, the National Animal Health Monitoring System is designed to provide statistically-valid estimates of disease incidence and costs across broad geographic areas, potentially benefiting all those interested in the economics of livestock diseases in the United States.
Mechanisms that restrict the intraintestinal niches of helminths (as indicated by the sites they occupy) can be favored by several selection pressures. These selection pressures act on different scales, and may interact to have different effects in different circumstances. In addition, the end results may not reflect responses to the niche, but be a by-product of other processes, such as the immune responses of the host.
Free thyroxin (FT4) concentrations, total thyroxin/thyroxin-binding globulin (T4/TBG) ratios, and thyrotropin (TSH) and albumin concentrations were measured in serum in a longitudinal study in each of the three trimesters of 25 normal pregnancies. In late pregnancy, FT4 estimates by assays reputedly either affected or unaffected by albumin were in the lower half of the reference range for nonpregnant subjects. T4/TBG ratios and albumin concentrations were similarly lower. FT4 overall was significantly (P less than 0.001) correlated with these latter two values. Serum TSH concentrations increased as FT4 declined in late pregnancy. Nonesterified fatty acid (NEFA) concentrations were too low to displace T4 from its binding proteins and were not correlated with other measurements. Within any one of the trimesters, FT4 and T4/TBG were independent of variations in TBG or albumin concentrations. This implies that lower FT4 concentrations in late pregnancy are real, merely coinciding with parallel decreases in albumin. They are not artefacts of albumin-affected assays.
The significance of interspecific interactions as a structuring force in the enteric helminth communities of 4 species of grebes (Aechmophorus occidentalis, Podiceps grisegena, P. nigricollis, and P. auritus) was evaluated. Patterns of microhabitat distribution revealed that helminths resided in predictable locations along the length of the small intestine. Individual species of helminths occupied a high proportion of the intestine and varied in position in different host species suggesting a broad tolerance for conditions along the intestine. However, in individual birds, helminths were much more restricted in distribution, overlapped considerably less than their overall ranges would suggest, congeners had complementary distributions, and there was evidence of interference by at least 1 core species, all suggesting that interactions are important in these communities. Nevertheless, vacant niches were present in most birds, and core species were not distributed more evenly than would be expected through random placement. This suggests that important resources may not be distributed evenly along the intestinal gradient.
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Twelve free-ranging Rocky Mountain bighorn lambs (Ovis canadensis canadensis), each exposed experimentally to 125-1,000 infective third-stage larvae of Protostrongylus stilesi and P. rushi, shed significantly more first-stage larvae in their feces than did control lambs, but showed no clinical signs of illness and had equivalent summer and overwinter survival as control lambs. Two adult ewes, each exposed to 925 infective larvae, showed no increase in numbers of first-stage larvae in their feces; both survived at least 14 mo postexposure. Experimentally exposed lambs did not differ from control lambs in numbers of larvae in their feces in the following summer. Three experimental lambs had 313-402 adult P. stilesi and 0-97 adult P. rushi on necropsy; two control lambs had 255 and 270 P. stilesi and no P. rushi. The presence of these numbers of lungworms did not appear to be sufficient to precipitate lungworm pneumonia in bighorn lambs under the conditions of this study.
The arrest of B16 melanoma cells and the subsequent development of tumors have been studied following left intraventricular injections (LVI) into mice of radiolabelled and unlabelled cells respectively; the proportions of cardiac output going to different target organs were also determined by LVI of radiolabelled microspheres. B16 cell arrest in the various target organs was as predicted by relative arterial blood supply, except in the lungs and liver where more radioactive counts were detected than could be accounted for in terms of initial arterial dissemination alone; and the numbers of counts remaining in all organs after 24 h were related to the numbers of counts initially obtained. When the incidence of tumor-bearing organs was related to the cell arrest patterns, the organs could be divided into two major distinct groups. Within both of these groups, the patterns of tumor incidence were correlated with cancer cell delivery. These results on a model system suggest that the two major hypotheses used to account for metastatic patterns are not mutually exclusive: the "soil" effect divides the target organs into the two major groups; however, within these groups the incidence of tumors is explicable in terms of the "mechanical" hypothesis.
Following the injection of B16 melanoma cells into the portal veins of mice, all animals developed liver tumors, but only 16% developed lung tumors. Portal vein injections of radiolabelled B16 and Walker 256 cancer cells into mice and rats, respectively, revealed that all of the cells were temporarily arrested in the liver and most were then slowly released. Bioassays indicated that of 8 X 10(4) B16 cells released from the liver over 24 h after portal vein injections of 10(5) cells, only approximately 1% were delivered to the lungs in a viable state. Experiments made with radiolabelled B16 cells showed that transit through either the liver or lungs following portal vein or tail vein injections, respectively, resulted in massive death of cancer cells. It is suggested that the death of most circulating cancer cells passing through the first organ encountered after leaving their primary tumor, serves to severely limit their further direct spread to other organs. It is therefore expected that metastases to these other organs would, to a large extent, be generated by cancer cells from metastases in the "first organs" as distinct from direct seeding from cancer cells released from the primary tumor. If the results of the present experiments have general application, they serve to emphasize the importance of metastasis of metastases in the natural history of the spread of cancer. In a previous publication (Weiss, 1980), studies of lung-to-liver traffic of cancer cells in rats revealed that, after tail vein injections, most Walker 256 cells were temporarily arrested in the pulmonary vasculature and then slowly released. A large proportion of the released cancer cells were dead or lethally injured on release from the lungs, and this "first organ processing" apparently accounted for the comparative rarity of extrapulmonary tumors following tail vein injections. In this communication, the concept of "first organ processing" of circulating cancer cells is further examined with respect to the liver-to-lung traffic of B16 melanoma and Walker 256 cells injected into the portal veins of mice or rats respectively. Both of these cell types grow well in the lungs following tail-vein injection.
The hypothesis that metastases arise from pre-existing metastatic sub-populations of cancer cells with heritable metastasis-related characteristics, was tested by comparing the metastatic behaviour of cancer cells derived from pulmonary metastases with those from corresponding primary tumours, after implanting them subcutaneously in mice. In the case of KHT osteosarcomas and B16 melanomas, injected minces of metastases gave rise to more pulmonary metastases than cells derived from minces of the primary cancers generating them. However, in the case of 3LL and T241 cancers, the primary tumour minces gave rise to more pulmonary metastases than those derived from minced metastases. It is therefore concluded that the subpopulation hypothesis cannot be accepted as a general rule. When fragments of solid tumours were implanted into animals, no differences were detected between the metastatic behaviour of implants taken randomly from pulmonary metastases and the volume/age matched primary tumours generating them. These experiments thus provide no support for the hypothesis that metastases arise exclusively or predominantly from pre-existing metastatic subpopulations of cancer cells. Finally, implants of matched fragments from 3LL tumours of different volume and age, essentially produced no statistically significant differences in numbers of metastases. These observations do not therefore support the concept of a progressive evolution of subpopulations of cancer cells with heritable metastatic phenotypes during tumour growth.
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Cardiac tamponade is associated with decreased cardiac output and increased systemic vascular resistance. Thus, vasodilator drugs might lower systemic resistance and increase cardiac output. Three groups of dogs were studied during tamponade. Group I received nitroprusside only; group II received blood transfusion and then nitroprusside; group III received hydralazine. In group I, nitroprusside lowered right artrial pressure and systemic resistance; cardiac output was unchanged. In group II, transfusion raised right atrial pressure but not cardiac output. Then nitroprusside raised cardiac output significantly. Hydralazine decreased right atrial pressure less than nitroprusside but decreased vascular resistance and raised cardiac output. Both nitroprusside and hydralazine decreased systemic vascular resistance during tamponade, but only hydralazine raised cardiac output probably because of its lesser effect upon the capacitance vessels. Nitroprusside maintained cardiac output during tamponade despite lowered right atrial pressure but increased cardiac output only after transfusion.
Tardy ulnar nerve palsy in the child is an infrequent occurrence. In 5 cases all occurring after injury about the elbow, the lesion involved not only lateral but also medial structures. The latency period from elbow injury to palsy was not always long and ranged from 2 months to 29 months. Possibly because of the age of the patients and short duration of the palsy, anterior transposition promoted prompt remission of symptoms and signs.