The Effects of Long-term Molybdenum Exposure in Drinking Water on Molybdenum Metabolism and Production Performance of Beef Cattle Consuming a High Forage Diet.

Fifty-four multiparous beef cows with calves were used to evaluate the effects of Mo source (feed or water) on reproduction, mineral status, and performance over two cow-calf production cycles (553 days). Cows were stratified by age, body weight, liver Cu, and Mo status and were then randomly assigned to one of six treatment groups. Treatments were (1) negative control (NC; basal diet with no supplemental Mo or Cu), (2) positive control (NC + Cu; 3 mg of supplemental Cu/kg DM), (3) NC + 500 µg Mo/L from Na2MoO4·2H2O supplied in drinking water, (4) NC + 1000 µg Mo/L of Na2MoO4·2H2O supplied in drinking water, (5) NC + Mo 1000-water + 3 mg of supplemental Cu/kg DM, and (6) NC + 3.0 mg of supplemental Mo/kg diet DM from Na2MoO4·2H2O. Animals were allowed ad libitum access to both harvested grass hay (DM basis: 6.6% crude protein; 0.15% S, 6.7 mg Cu/kg, 2.4 mg Mo/kg) and water throughout the experiment. Calves were weaned at approximately 6 months of age each year. Dietary Cu concentration below 10.0 mg Cu/kg DM total diet reduced liver and plasma Cu concentrations to values indicative of a marginal Cu deficiency in beef cows. However, no production parameters measured in this experiment were affected by treatment. Results suggest that Mo supplemented in water or feed at the concentrations used in this experiment had minimal impact on Cu status and overall performance.

Satellite ionosonde records: resonances below the cyclotron frequency.

Resonant responses observed by the topside ionosonde in the Canadian satellite Alouette II are examined. In addition to the well-known plasma resonances, several subsidiary resonances are identified below the electron cyclotron frequency. Their patterns of occurrence are not consistent with a suggested explanation of induced magnetic dipole radiation; rather they appear to result from harmonic stimulation of the plasma resonances and beat-frequency generation.

Odontoid metastasis: a potential lethal complication.

Nearly one third of cervical spine metastasis has a primary breast malignancy. Patients with cervical metastasis have higher mortality due to advanced stage of the malignancy. Treatment is palliative to relieve pain, prevent pathological fracture, improve mobility and function, and prolong survival. We describe a 40-year-old woman with a history of breast cancer who presented with neck and shoulder pain of 1 week duration with no neurological deficit. Following clinical examination, radiographs taken of the cervical spine was normal. Radiographs repeated 3 weeks later revealed a large lytic lesion of the odontoid occupying 70-80% of the peg. Further investigation including magnetic resonance imaging and bone scan showed no further spinal lesions. She underwent cyclical radiotherapy with complete resolution of the odontoid peg lesion and clinically was asymptomatic at 2 years. Metastatic lesions of the odontoid are atypical, and this case reinforces the necessity of early detection to evade disastrous consequences.

A farnesyltransferase inhibitor induces tumor regression in transgenic mice harboring multiple oncogenic mutations by mediating alterations in both cell cycle control and apoptosis.

The farnesyltransferase inhibitor L-744,832 selectively blocks the transformed phenotype of cultured cells expressing a mutated H-ras gene and induces dramatic regression of mammary and salivary carcinomas in mouse mammary tumor virus (MMTV)-v-Ha-ras transgenic mice. To better understand how the farnesyltransferase inhibitors might be used in the treatment of human tumors, we have further explored the mechanisms by which L-744,832 induces tumor regression in a variety of transgenic mouse tumor models. We assessed whether L-744,832 induces apoptosis or alterations in cell cycle distribution and found that the tumor regression in MMTV-v-Ha-ras mice could be attributed entirely to elevation of apoptosis levels. In contrast, treatment with doxorubicin, which induces apoptosis in many tumor types, had a minimal effect on apoptosis in these tumors and resulted in a less dramatic tumor response. To determine whether functional p53 is required for L-744,832-induced apoptosis and the resultant tumor regression, MMTV-v-Ha-ras mice were interbred with p53(-/-) mice. Tumors in ras/p53(-/-) mice treated with L-744,832 regressed as efficiently as MMTV-v-Ha-ras tumors, although this response was found to be mediated by both the induction of apoptosis and an increase in G1 with a corresponding decrease in the S-phase fraction. MMTV-v-Ha-ras mice were also interbred with MMTV-c-myc mice to determine whether ras/myc tumors, which possess high levels of spontaneous apoptosis, have the potential to regress through a further increase in apoptosis levels. The ras/myc tumors were found to respond nearly as efficiently to L-744,832 treatment as the MMTV-v-Ha-ras tumors, although no induction of apoptosis was observed. Rather, the tumor regression in the ras/myc mice was found to be mediated by a large reduction in the S-phase fraction. In contrast, treatment of transgenic mice harboring an activated MMTV-c-neu gene did not result in tumor regression. These results demonstrate that a farnesyltransferase inhibitor can induce regression of v-Ha-ras-bearing tumors by multiple mechanisms, including the activation of a suppressed apoptotic pathway, which is largely p53 independent, or by cell cycle alterations, depending upon the presence of various other oncogenic genetic alterations.

Differential regulation of cell cycle characteristics and apoptosis in MMTV-myc and MMTV-ras mouse mammary tumors.

We have used the MMTV-myc and MMTV-ras transgenic mouse mammary tumor models (T. A. Stewart et al., Cell, 38: 627-637, 1984, and E. Sinn et al., Cell, 49: 465-475, 1987) to evaluate how the c-myc and v-Ha-ras oncogenes influence tumor growth characteristics in vivo. MMTV-myc tumors had much higher levels of spontaneous apoptosis than MMTV-ras tumors, whereas intermediate levels were observed in MMTV-myc/ras tumors. Significant differences in cell cycle characteristics were also observed in tumors from mice of the three genotypes. Tumors from MMTV-myc mice had lower G1 and higher S-phase fractions than MMTV-ras tumors, with intermediate values again observed in the MMTV-myc/ras tumors. Despite these differences, however, tumor growth rates for the different groups were similar. These findings highlight the importance of the balance between cell cycle regulation and cell death in determining the kinetics of tumor growth and indicate that distinct oncogenes can have a profound influence on that balance.

A Phase I and pharmacokinetic study of temozolomide and cisplatin in patients with advanced solid malignancies.

Temozolomide (TMZ) is an oral imidazotetrazinone that is spontaneously converted to 5-(3-methyltriazen-1-yl)imidazole-4-carboxamide (MTIC) at physiological pH. MTIC methylates DNA at the O6 position of guanine, although this lesion may be repaired by the enzyme O6-alkylguanine-DNA alkyltransferase (AGAT). In this study, TMZ was combined with cisplatin (CDDP), because both agents have single-agent activity against melanoma and other tumor types. Additionally, CDDP has been shown to inactivate AGAT, and subtherapeutic concentrations of CDDP have been shown to increase the sensitivity of leukemic blasts to TMZ. This Phase I study sought to determine the toxicities, recommended dose, and pharmacological profile of the TMZ/CDDP combination. Patients were treated with oral TMZ daily for 5 consecutive days together with CDDP on day 1 (4 h after TMZ) every 4 weeks at the following TMZ (mg/m2/day)/CDDP (mg/m2) dose levels: 100/75, 150/75, 200/75, and 200/100. Plasma samples were obtained on days 1 and 2 to evaluate the pharmacokinetic parameters of TMZ alone and in combination with CDDP. Fifteen patients received a total of 44 courses of TMZ/CDDP. The principal toxicities of the regimen consisted of neutropenia, thrombocytopenia, nausea, and vomiting, which were intolerable in two of six new patients treated at the 200/100 mg/m2 dose level. Of five patients receiving 17 courses at the next lower dose level (200/75 mg/m2), none experienced dose-limiting toxicity. Antitumor activity was observed in patients with non-small cell lung cancer, squamous cell carcinoma of the tongue, and leiomyosarcoma of the uterus. Pharmacokinetic studies of TMZ revealed the following pertinent parameters (mean +/- SD): time to maximum plasma concentration (Tmax) = 1.1+/-0.6 h (day 1) and 1.7+/-0.9 h (day 2); elimination half-life (t1/2) = 1.74+/-0.22 h (day 1) and 2.35+/-0.70 h (day 2); and clearance (Cl(s)/F) = 115+/-27 ml/min/m2 (day 1) and 141+/-109 ml/min/m2 (day 2). TMZ drug exposure, described by the area under the plasma concentration-time curve (AUCinfinity) and the maximum plasma concentration (Cmax), was similar on days 1 and 2. On the basis of these results, the recommended doses for Phase II clinical trials are TMZ 200 mg/m2/day for 5 days with 75 mg/m2 CDDP on day 1, every 4 weeks. The addition of CDDP did not affect the tolerable dose of single-agent TMZ (200 mg/m2/day x 5 days), nor did it substantially alter the pharmacokinetic behavior of TMZ.

Are we overusing blood transfusing after elective joint replacement?--a simple method to reduce the use of a scarce resource.

OBJECTIVES: To determine the proportion of patients who received a blood transfusion after joint replacement, and to devise a simple method to ensure patients were transfused based on strict clinical and haematological need. DESIGN: Prospective audit over 2 years. PATIENTS AND METHODS: The study group was 151 patients who underwent total hip and knee arthroplasty in a typical district general hospital (Kettering) over a 2-year period. They were divided into three consecutive groups. Current practice was audited (producing the first group of 62 patients) and transfusion rates were compared to regional figures. Local guidelines were drawn up. A form was introduced on which the indications for any transfusion had to be documented prior to transfusion of the blood. This was designed to encourage transfusion only on strong clinical grounds or an haemoglobin (Hb) level < 8 g/dl. Transfusion practice was then re-audited (producing the second group of 44 patients) to assess whether practice had improved. A year later, all relevant staff were reminded by letter of the guidelines. The process was then re-audited (producing the third group of 45 patients) again to determine whether practice remained improved or not. RESULTS: In the first audit (current practice) of 62 patients, the overall transfusion rate was 71%, with a higher rate in the hip replacement group (84%) ordered mainly by anaesthetic staff. Ward staff were reluctant not to transfuse patients whose Hb level fell below 10 g/dl. In the second audit, the transfusion rate fell by nearly 50% to 37%, with almost identical figures for knee and hip replacement. In the third audit of 45 patients, a year later, the transfusion rate was 40% overall. CONCLUSIONS: Patients were being transfused routinely, generally without good clinical evidence of benefit to the patient. The audit process was successful in instituting change for the better in blood transfusion practice for elective joint replacement. The improved practice can be largely maintained provided staff are regularly reminded of appropriate guidelines and encouraged to transfuse for clinical need only. For absolute adherence to guidelines, we would recommend a compulsory form system be introduced for transfusion in the per-operative period, to ensure blood transfusion is only given when absolutely necessary.

T-cell receptor polymorphisms in Tlingit Indians with rheumatoid arthritis.

Rheumatoid arthritis (RA) develops as a result of the interaction of both genetic and environmental factors. Among the genes in humans that have been suggested as candidate susceptibility genes in RA are those encoding the T cell receptor for antigen (TCR). A high prevalence and early age of onset of RA has previously been reported in Alaskan Tlingit Indians. In this study, the frequency of seven different restriction fragment length polymorphisms (RFLPs) in the TCR alpha and beta gene complexes were measured in a population of Alaskan Tlingit Indians. No statistically significant differences were noted when the frequencies of these RFLPs were compared between Tlingits with RA and healthy controls (p > 0.05). These results do not support the hypothesis of an RA-susceptibility allele in the vicinity of these TCR alpha or beta genes. Since TCR RFLPs have not been extensively studied in native American populations, TCR polymorphism frequencies in the Tlingits were also compared to the frequencies observed in a second control group of healthy Caucasians. Statistically significant differences were observed in these comparisons implying a different distribution of individuals in these populations with different TCR repertoires.

Single-blind study of diflunisal versus mefenamic acid in the treatment of pain after Colles' fracture.

A single-blind study was carried out in 52 patients with severe pain after Colles' fracture to assess the analgesic efficacy and tolerability of 500 mg diflunisal twice daily compared with that of 500 mg mefenamic acid given 3-times daily over a period of 5 days. The results showed that both treatments were effective in relieving pain, night pain and limitation of movement by pain, and there was no significant difference between the response in the two groups. Both drugs were tolerated and only 3 patients (2 on diflunisal) reported mild drug-related side-effects.

Internal fixation versus hemiarthroplasty for the displaced subcapital fracture of the femur. A prospective randomised study.

A prospective randomised trial of surgical treatment for the displaced subcapital femoral fracture in patients of 70 years or more is presented. Two hundred and eighteen patients were randomly allocated into one of three treatment groups: manipulative reduction and internal fixation using Garden screws; Thompson hemiarthroplasty through a posterior (Moore) approach; and Thompson hemiarthroplasty through an anterolateral (McKee) approach. There is no significant difference in the mortality of the internal fixation and posterior arthroplasty groups. Both groups showed a significantly higher mortality than patients operated on through the anterior approach. The technical results of operation were worse in the internally fixed group, with only 40 per cent being satisfactory. Mobilisation was best achieved after the posterior approach. It is concluded that Thompson hemiarthroplasty, using an anterolateral approach, is the safest operation in this group of patients.

Metatarsus primus varus. A statistical study.

A survey of 6000 schoolchildren discovered 36 cases of unilateral and 60 cases of bilateral hallux valgus, defined as a metatarsophalangeal angle of more than 14.5 degrees, measured on standing radiographs. Metatarsus primus varus was found not only in the early stages of hallux valgus but in the unaffected feet of children with unilateral hallux valgus. Adduction of the first metatarsal is not due to differential growth of the cortices of the first metatarsal nor is it a consequence of malalignment of the metatarsocuneiform joint. The intermetatarsal angle did not correlate with the angle of metatarsus adductus nor with the intercuneiform angle.

A controlled prospective trial of a foot orthosis for juvenile hallux valgus.

In a survey of 6000 children between 9 and 10 years of age, 122 were found to have unilateral or bilateral hallux valgus. These children were randomly assigned to no treatment or to the use of a foot orthosis. About three years later 93 again had radiography. The metatarsophalangeal joint angle had increased in both groups but more so in the treated group. During the study, hallux valgus developed in the unaffected feet of children with unilateral deformity, despite the use of the orthosis.

Variations of serum vitamin E, cholesterol, and total serum lipid concentrations in horses during a 72-hour period.

Fluctuations of serum vitamin E (alpha-tocopherol), cholesterol, and total lipids were monitored in 12 horses at 3-hour intervals for 72 hours. Mean coefficients of variation were 12, 5, and 15%, respectively. Statistical analyses were used to conclude that instrumentation error was accountable for only a small portion of the vitamin E variation. Results indicated that a single serum sample assay is an unsatisfactory indicator of vitamin E status in horses. These data have clinical application in the evaluation of horses suspected to be affected with equine degenerative myeloencephalopathy. The large variance of serum total lipids and the lack of correlation of it with serum vitamin E over time preclude the use of vitamin E/serum total lipids ratio in assessing vitamin E status.

Variability of alpha-tocopherol values associated with procurement, storage, and freezing of equine serum and plasma samples.

Recent evidence concerning the pathogenesis of equine degenerative myeloencephalopathy indicated that low blood alpha-tocopherol values are a factor in the disease process. Variables that could be introduced by a veterinarian procuring, transporting, or storing samples were evaluated for effects on alpha-tocopherol concentration in equine blood. These variables included temperature; light; exposure to the rubber stopper of the evacuated blood collection tube; hemolysis; duration of freezing time, with and without nitrogen blanketing; and repeated freeze/thaw cycles. It was found that hemolysis caused the greatest change in high-performance liquid chromatography-measured serum alpha-tocopherol values, with mean decrease of 33% (P < 0.001). Lesser, but significant (P < 0.01) changes in serum alpha-tocopherol values were an approximate 10% decrease when refrigerated blood was left in contact with the red rubber stopper of the blood collection tube for 72 hours and an approximate 5% increase when blood was stored at 20 to 25 C (room temperature) for 72 hours. Repeated freeze/thaw cycles resulted in a significant (P < 0.05) 3% decrease in alpha-tocopherol values in heparinized plasma by the third thawing cycle. Freezer storage for a 3-month period without nitrogen blanketing resulted in slight (2%) decrease in mean serum alpha-tocopherol values, whereas values in serum stored for an identical period under nitrogen blanketing did not change. A significant (P < 0.001) mean decrease (10.3%) in alpha-tocopherol values was associated with freezer (-16 C) storage of nitrogen blanketed serum for 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of a moulded metacarpal brace versus neighbour strapping for fractures of the little finger metacarpal neck.

Seventy-three patients with fractures of the neck of the little finger metacarpal were randomized to treatment with a moulded metacarpal brace or neighbour strapping. Sixty-five of these attended for follow-up at 3 weeks. Both treatment modalities permitted a functional range of movement, but patients treated with the metacarpal brace had significantly less pain than those treated with neighbour strapping, and this facilitated an early return to work.

Bisphosphonates in the prevention and treatment of glucocorticoid-induced osteoporosis.

OBJECTIVE: To summarize the literature concerning the use of bisphosphonates in the prevention and treatment of corticosteroid-induced osteoporosis and make recommendations concerning the proper use of these agents. SEARCH STRATEGIES: We conducted a literature search to identify studies in the English language concerning the use of bisphosphonates in the prevention or treatment of corticosteroid-induced osteoporosis using the MEDLINE, CURRENT CONTENTS, and HEALTHSTAR electronic databases, bibliographies of selected citations, and recent meeting abstracts. SELECTION CRITERIA: We included randomized controlled trials evaluating the use of oral bisphosphonates in adults by central dual X-ray absorptiometry. DATA COLLECTION AND ANALYSIS: We assessed the methodologic quality of the trials using the Jadad criteria. Data were collected concerning bone mineral density (BMD) changes in multiple areas, fracture rates, safety, and tolerability. MAIN RESULTS: Bisphosphonates generally increased BMD at the lumbar spine. Data were less clear concerning changes in the femoral area. Little information exists about the ability of bisphosphonates to reduce fracture risk in patients with corticosteroid-induced osteoporosis. Postmenopausal women seemed to receive the most benefit. CONCLUSIONS: Bisphosphonates significantly increased BMD in patients at risk for corticosteroid-induced bone loss. However, there is a sparsity of data concerning the ability of these agents to affect the clinically important outcome of fracture rate reduction, especially among premenopausal women in whom fractures are rare within the first year or 2 of exposure to corticosteroids. Long-term studies powered to detect fracture risk reduction are needed as well as comparative trials with bisphosphonates and other agents.

Somatic diversification of IgH genes in rabbit.

Rabbits have helped elucidate one of the major immunologic puzzles, namely the genetic control of antibody diversity. The primary IgH antibody repertoire in rabbits is dominated by B cells that use the same germline VH-gene segment in VDJ gene rearrangements. The VDJ genes of essentially all B lymphocytes undergo somatic diversification within the first few weeks of the rabbit's life. Such diversification occurs both by a somatic gene conversion-like mechanism as well as by somatic hyperpointmutation. The diversification that occurs early in ontogeny takes place in gut-associated lymphoid tissues and potentially depends on external factors such as microbial antigens. Few, if any, new B lymphocytes develop in adult rabbits and we discuss how the antibody repertoire is maintained throughout life. Finally, we discuss the molecular mechanism of somatic gene conversion of Ig genes, including the possibility that this involves the use of RAD51, an enzyme required for gene conversion-mediated mating type switch in yeast.

A role for RAD51 in the generation of immunoglobulin gene diversity in rabbits.

Ig VDJ genes in rabbit somatically diversify by both hyperpointmutation and gene conversion. To elucidate the mechanism of gene conversion of IgH genes, we cloned a rabbit homologue of RAD51, a gene involved in gene conversion in Saccharomyces cerevisiae (yeast), and tested whether it could complement a yeast rad51 mutant deficient in recombination repair. We found that rabbit RAD51 partially complemented the defect in switching mating types by gene conversion as well as in DNA double-strand break repair after gamma-irradiation. Further, by Western blot analysis, we found that levels of Rad51 were higher in appendix-derived B lymphocytes of 6-wk-old rabbits, a time at which IgH genes diversify by somatic gene conversion. We suggest that Rad51 is involved in somatic gene conversion of rabbit Ig genes.

The role of complement in inflammation and adaptive immunity.

Major advances in our understanding of the immunobiology of complement were made within the past 5 years primarily due to the development of gene-targeting technology. New strains of mice bearing specific deficiencies in serum complement proteins or their receptors were developed using this approach. Characterization of these mice has provided new and exciting insights into the biology of the complement system. In this review, we discuss recent results on two important aspects of the complement system, i) host protection and inflammation, and ii) regulation of B lymphocytes of adaptive immunity. While these two roles appear distinct, they are linked. We discuss how natural antibody and classical pathway complement work together in host protection against bacterial infection on the one hand but, on the other, they co-operate to induce inflammation as observed in reperfusion injury. Significantly, the lymphocytes that produce natural antibody, the B-1 lymphocytes, are regulated in part by the complement system.

Dw14(DRB1*0404) is a Dw4-dependent risk factor for rheumatoid arthritis. Rethinking the "shared epitope" hypothesis.

HLA-DR4 has been shown to be associated with risk for developing rheumatoid arthritis (RA) in multiple populations and racial groups. The allelic variants of DR4 share the DR4 serologic specificity but differ by 1 to 3 amino acids in the third hypervariable region (positions 67 to 74) and at positions 57 and 86 of the DR beta 1 chain. We have examined DR4 variants in 61 DR4+ RA cases and 55 DR4+ healthy controls. Dw14 was not associated with RA risk in DR4 heterozygous (DR4,X) cases. Only 15% of DR4,X cases had the Dw14 allele compared with 28% of DR4,X controls. In homozygous (DR4,4) individuals who also expressed Dw4, however, Dw14 was associated with increased RA risk. Moreover, the relative risk for Dw4,Dw14 (16.1, p = 0.001) actually exceeded that of Dw4,Dw4 (2.2, p = ns). Thus Dw14 is not an independent risk factor for RA but is a synergistic risk factor for individuals who also have the Dw4 allele.