Evaluation of apheresis platelet concentrates collected with a reduced (30-ml) collection chamber with resuspension and storage in a synthetic medium

Recently, the CS-3000 Plus Blood Cell Separator with the TNX-6 platelet separation chamber insert has been furnished with a small-volume (30-ml) collection chamber. In this study, a platelet synthetic medium containing glucose and bicarbonate (PSM) was used for resuspension and storage of this highly concentrated platelet product. Eighteen donors participated in a paired study design where each participant donated platelets on two occasions, once following collection in a standard chamber with resuspension and storage in plasma and once following collection in the new chamber with resuspension and storage in PSM. Substantially higher total platelet counts were obtained using platelets collected in the small chamber and stored in PSM as compared to control (4.4 +/- 0.9 x 10(11) vs. 3.5 +/- 0.9 x 10(11) platelets, p < 0.01 by paired t test). After 5 days of storage, PSM-stored platelets demonstrated higher ATP levels, less lactate dehydrogenase in the supernatant and increased lactate production with resulting lower pH at day 5 of storage (6.94 +/- 0.15 vs. 7.08 +/- 0.09, p < 0.05). There were no statistically significant differences of the survival by multiple-hit estimation of PSM-stored as compared to plasma-stored platelets as determined by 111In labeling and infusion. A slight decrease in the initial percent recovery with the additive-suspended as compared to suspended plasma cells was noted: 50 +/- 8 versus 54 +/- 9%, respectively (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Spinal bone loss in postmenopausal women supplemented with calcium and trace minerals

The effects of calcium supplementation (as calcium citrate malate, 1000 mg elemental Ca/d) with and without the addition of zinc (15.0 mg/d), manganese (5.0 mg/d) and copper (2.5 mg/d) on spinal bone loss (L2-L4 vertebrae) was evaluated in healthy older postmenopausal women (n = 59, mean age 66 y) in a 2-y, double-blind, placebo-controlled trial. Changes (mean +/- SEM) in bone density were -3.53 +/- 1.24% (placebo), -1.89 +/- 1.40% (trace minerals only), -1.25 +/- 1.46% (calcium only) and 1.48 +/- 1.40% (calcium plus trace minerals). Bone loss relative to base-line value was significant (P = 0.0061) in the placebo group but not in the groups receiving trace minerals alone, calcium alone, or calcium plus trace minerals. The only significant group difference occurred between the placebo group and the group receiving calcium plus trace minerals (P = 0.0099). These data suggest that bone loss in calcium-supplemented, older postmenopausal women can be further arrested by concomitant increases in trace mineral intake.

Timing of peak bone mass in Caucasian females and its implication for the prevention of osteoporosis. Inference from a cross-sectional model

To determine the timing of peak bone mass and density, we conducted a cross-sectional study of bone mass measurements in 265 premenopausal Caucasian females, aged 8-50 yr. Bone mass and bone mineral density were measured using dual X-ray absorptiometry and single-photon absorptiometry at the spine (anteroposterior, lateral), proximal femur, radius shaft, distal forearm, and the whole body. Bone mass parameters were analyzed using a quadratic regression model and segmented regression models with quadratic-quadratic or quadratic-linear form. The results show that most of the bone mass at multiple skeletal locations will be accumulated by late adolescence. This is particularly notable for bone mineral density of the proximal femur and the vertebral body. Bone mass of the other regions of interest is either no different in women between the age of 18 yr and the menopause or it is maximal in 50-yr-old women, indicating slow but permanent bone accumulation continuing at some sites up to the time of menopause. This gain in bone mass in premenopausal adult women is probably the result of continuous periosteal expansion with age. Since rapid skeletal mineral acquisition at all sites occurs relatively early in life, the exogenous factors which might optimize peak bone mass need to be more precisely identified and characterized.

Effect of age, calcium source, and radiolabeling method on whole body 47Ca retention in the rat

In a longitudinal study we determined the effect of animal age as well as Ca source and radiolabeling method on Ca bioavailability by measuring whole body 47Ca retention (WBR) in male Sprague-Dawley rats. The WBR assay was performed without surgery or anesthesia, and the same groups of animals were studied at 8, 16, 20, and 32 wk of age. Rats were administered a 6-mg radiolabeled oral dose of Ca as Ca citrate malate (CCM) or intrinsically or extrinsically labeled CaCO3 or hydroxyapatite (HAP). Fractional Ca retention was measured from the 72-h postdose WBR divided by WBR at time 0. WBR was significantly affected by Ca source with CCM > CaCO3 > HAP at all ages (P < 0.001). The rank order and relative bioavailabilities of these Ca salts in the rat model agreed well with literature values for Ca absorption in adult humans. Although percent WBR decreased significantly with advancing age (P < 0.001), the mean rate of decline (-3.4%/wk) was not affected by Ca source. Extrinsic radiolabeling overestimated (approximately 20%) Ca bioavailability when the rats were young. However, the magnitude of this effect diminished with advancing animal age and was not significant across all ages (repeated measures analysis of variance P = 0.10).

BPV-4 induces amplification and activation of 'silent' BPV-1 in a sub-line of C127 cells

BPV-4-induced malignant transformation of C127 mouse fibroblasts in vitro is the result of a 'hit and run' mechanism. Viral DNA is lost on continued subculture of transformed cell lines without loss of any malignant characteristics. The DNA from these cells harbours specific amplified sequences. Two such amplified fragments of approximately 10 kb and 12 kb were molecularly cloned and designated HL-10 and HL-12 respectively. HL-10 transformed C127 cells efficiently and therefore encodes a transforming function, whereas the 12 kb clone did not. Heteroduplexes showed that HL-12 was homologous to HL-10 except for two additional tandem copies of an approximately 1.7 kb sequence. Sequence analysis of HL-10 revealed that the clone contained a 5.2 kb region from BPV-1 including the transforming ORFs. Transformation studies have shown differences between HL-10 and BPV-1, indicating that the host flanking sequences may contribute to the transforming potential of the BPV-1 ORFs. The BPV-1 DNA was associated with sequences homologous to murine autonomously replicating sequences (ARS) implicated in the establishment of multiple tandem DNA repeats. As the parental cells contain the set of sequences amplified in transformed cells in single copy and show none of the characteristics of transformed cells, we conclude that BPV-4 has activated these sequences by amplification and rearrangement. These phenomena may be mediated through an interaction between BPV-4 proteins and the BPV-1 origin of DNA replication or via the ARS region.

Intraduodenal delivery of intrinsically and extrinsically labelled CaCO3 in the rat: effect of solubilization on calcium bioavailability

The dissolution of CaCO3 before intraduodenal administration was found to be an important factor determining calcium (Ca) bioavailability. Extrinsically and intrinsically labelled 47CaCO3 preparations were sequentially dissolved by serial additions of HCl. Aliquots of these preparations were collected before (no HCl added) and during the solubilization process and administered intraduodenally to rats. Whole body 47Ca retention 72 h post-dose was used as a measure of Ca bioavailability. Although dissolution of CaCO3 significantly increased Ca bioavailability (P < 0.001), Ca from both intrinsically and extrinsically labelled CaCO3 was absorbed and retained to some extent without prior acid dissolution. Due to a disproportionately high concentration of 47Ca on the particle surface, extrinsically labelled 47CaCO3 overestimated bioavailability when unsolubilized or partially solubilized CaCO3 preparations were used (P < 0.05). These data indicate that dissolution is a determining factor for Ca bioavailability from CaCO3. Incomplete dissolution will significantly limit but not completely prevent Ca bioavailability. The disintegration and dissolution characteristics of commercial CaCO3 preparations, which vary widely, may produce important differences in Ca absorption.

Association of bovine papillomavirus type 2 and bracken fern with bladder cancer in cattle

The bladder cancer syndrome that often accompanies chronic enzootic hematuria in cattle grazing on pastures infested by bracken fern has been experimentally reproduced in animals fed a diet of bracken. The experimentally induced tumors were histologically and pathologically indistinguishable from the naturally occurring ones and comprised two main types: (a) carcinoma of the urothelium identical to that seen in humans; and (b) hemangioendotheliomas of the subjacent capillaries. Often the two types of tumor occurred together in the same bladder. In animals experimentally immunosuppressed with azathioprine "bracken type" hemangiomas developed in the bladder lining. DNA of bovine papillomavirus (BPV) type 2 was found in 46% (7 of 15) of the natural cancer cases and in 69% (9 of 13) of the experimentally induced lesions, independently of histological type and including the hemangiomas of the azathioprine-treated animals, suggesting a close association between BPV and bovine bladder neoplasia. Moreover, BPV-2 DNA was found in experimental animals that had not been inoculated with BPV at all or had been inoculated with a different BPV type and had been kept in isolation, suggesting that BPV can persist in a latent state and be activated when the animal is exposed to the bracken cocarcinogens and to immunosuppressants.

Spinal bone density and calcium intake in healthy postmenopausal women

Dietary calcium intake and bone mineral density (BMD) of the lumbar spine (L2-L4) were determined in 131 healthy free-living postmenopausal women (aged 64.7 +/- 7.6 y, means +/- SD). The calcium consumption for the total population was 606 +/- 302 mg/d. Subjects consuming less than the population mean of dietary calcium had significantly lower BMDs than did subjects with intakes above the mean (P less than 0.009); these two groups did not differ in basic demographic characteristics. Additional analyses using a stepwise univariate regression model demonstrated that BMD was significantly associated with body weight (P less than 0.001) and dietary calcium intake (P less than 0.02). These data support the hypothesis that dietary calcium intake is a determinant of skeletal health in postmenopausal women.

Studies on vaccination against papillomaviruses: prophylactic and therapeutic vaccination with recombinant structural proteins

The L1 and L2 proteins of BPV-2 have been produced in Escherichia coli as beta-galactosidase fusion proteins. The fusion proteins have been used to vaccinate calves both prophylactically and therapeutically. The L1 fusion protein prevented tumor formation when administered before challenge with BPV-2, while the L2 fusion protein was very effective in promoting tumor rejection, independently from whether it was administered before or after challenge. Animals vaccinated with L1, but not with L2, responded rapidly with production of serum neutralizing antibodies, showing that this peptide contains B-cell-specific epitopes. The massive infiltration of lymphocytes in the tumors of L2-vaccinated animals suggests that the peptide contains epitopes specific for T-cells. The two structural proteins of BPV-2 therefore interact with both efferent arms of the immune system, and this observation allows the choice between two different types of antiviral vaccination.

Malignant transformation of a papilloma induced by bovine papillomavirus type 4 in the nude mouse renal capsule

A papillomatous cyst was induced by implanting bovine foetal palate epithelium, infected in vitro with bovine papillomavirus type 4 (BPV-4), beneath the renal capsule of a nude mouse. The benign tumour underwent malignant progression, developing into a squamous cell carcinoma with metastatic deposits in the spleen. The bovine origin of both the renal and splenic cancers was confirmed by the presence of bovine major histocompatibility complex class I antigens in the cancer cells and by sequencing the Harvey-ras 1 gene, which was shown to be of bovine origin. BPV-4 DNA was present in the residual papillomatous fronds of the renal cancer, but was absent from the carcinoma proper and for the splenic metastasis. These results confirm that BPV-4 is a carcinogenic agent and that its genetic information is not necessary for the maintenance of the malignant phenotype. Moreover the system provides the opportunity to investigate the role of viral and chemical carcinogens in an experimental system.

The B subgroup bovine papillomaviruses lack an identifiable E6 open reading frame

Analysis of the corrected DNA sequence for the bovine papillomavirus type 4 (BPV4) genome revealed that there is no open reading frame (ORF) that might encode an E6 protein. The other two B subgroup bovine papillomaviruses, BPV3 and BPV6, were found to have the same arrangement of ORFs in this region as BPV4. Thus, we conclude that E6 functions are either not required by these viruses or are performed by another viral (or host) protein. Furthermore, the position that might be expected to be occupied by E6, between the long control region and the E7 ORF, contains the E8 ORF, which has the potential to encode a 42-residue polypeptide with considerable similarity to the E5 transforming protein of BPV1. Therefore, it appears that during the evolution of the B subgroup of BPVs, genomic rearrangements may have occurred resulting in the present layout of the early ORFs.

Cooperation between bovine papillomavirus type 4 and ras in the morphological transformation of primary bovine fibroblasts

Primary bovine fibroblasts derived from foetal palate can be transformed by bovine papillomavirus type 4 DNA only in the presence of an activated ras gene, indicating that the virus does not encode all the information required for morphological transformation of non-established cells. A subgenomic fragment containing the complete E8 and E7 open reading frames (ORFs) induces transformation in cooperation with activated ras but transformation is abolished when the E7 ORF is deleted at the 3' end, showing that this ORF encodes a necessary transforming function. Transformation is more aggressive when the E8 and E7 ORFs are placed under the transcriptional control of the long terminal repeat of the mouse Moloney leukaemia virus, suggesting that the degree of transformation is dependent on the level of expression of these genes.

Studies on vaccination against papillomaviruses: the immunity after infection and vaccination with bovine papillomaviruses of different types

Calves, free of antibodies to bovine papillomaviruses (BPV), were reared in isolation. One was infected with BPV-2, developed tumours and was resistant to homologous reinfection. Groups of calves were infected with BPV-2, BPV-5 or BPV-6; they all developed and subsequently rejected type-specific tumours. They were then infected with BPV-4; they were not immune and oral papillomas were induced. Groups of animals were vaccinated by intramuscular preparations of purified BPV-4 and BPV-6 and were challenged with homologous virus; all were immune to reinfection. An earlier experiment had shown this to be true for BPV-2. Two calves, immune to BPV-6, were not immune to BPV-1. These experiments, although they do not cover all the possibilities of reciprocal immunisation and challenge, indicate that prophylactic immunity to a range of papillomaviruses is type-specific. This is the first clear demonstration of this phenomenon in the papillomavirus group.

Studies on vaccination against papillomaviruses: a comparison of purified virus, tumour extract and transformed cells in prophylactic vaccination

Calves were vaccinated with two preparations made from one cutaneous fibropapilloma induced by bovine papillomavirus type 2 (BPV-2). One vaccine consisted of homogenised tumour; the other contained purified virus only. Both produced resistance to a heavy challenge infection of BPV-2. One calf in the vaccinated group developed a small tumour and rejected it earlier than the control calves. It would appear likely that the prophylactic immune response was induced by viral structural proteins only and that tumour-specific antigens are unnecessary. Bovine fibroblasts were transformed in vitro by BPV-2 and administered as a vaccine; immunity was not induced.

General and histopathological results of a two-year study of rats fed semi-purified diets containing casein and soya protein

Two semi-purified diets, identical except for protein (soya or casein), and a Purina chow diet were fed to groups of Sprague-Dawley rats and compared over a 22-month period for effects on body weight, organ weight, feed consumption, feed efficiency, protein efficiency, organ-to-body-weight ratios, certain organ mineral levels, gross pathology and histopathology. Feed efficiency, protein efficiency, body weight, and most organ weights were higher in the groups fed soya and casein, while feed consumption and most organ-to-body-weight ratios were relatively lower. Significant increases in the final pathology findings in the groups fed soya and casein included nephrocalcinosis (in females), hepatocellular vacuolization, gastric trichobezoars (hairballs), ulcerative pododermatitis (hock ulcers) and splenomegaly. This study demonstrates that the long-term feeding of semi-purified diets is feasible. Moreover, the differences observed between the protein sources, that is, soya and casein, were minimal, which suggests that either protein source is acceptable for long-term feeding studies.

Computed tomographic imaging of the coronary arterial tree-use of local tomography

It has been demonstrated previously (see E.L. Ritman and A.A. Bove, in State of the Art in Quantitative Coronary Arteriography, p.67-78, 1986) that coronary artery anatomy can be visualized using high-speed, volume-scanning X-ray CT (computed tomography). In the current study it is demonstrated that local image reconstruction (i.e. the reconstruction kernel is ~2(+) mm long), as distinct from more conventional global image reconstruction (i.e. 200(+) mm kernel length), has the advantage of reducing the need for operator interactive image processing. In addition, the local reconstruction algorithm eliminates the need for recording the X-ray projection data over the full transaxial extent of the thorax because it requires only the X-ray attenuation data over the region of the heart. This latter aspect reduces the dynamic range requirements for the sensors and could reduce total X-ray exposure.

Effects of different calcium sources on iron absorption in postmenopausal women

We measured the effect of calcium from food and supplement sources on whole-body retention of 59Fe in 19 normal postmenopausal women. Each woman received a placebo and 500 mg calcium from a mixed calcium citrate-malate salt (CCM), from orange juice plus CCM, and from milk after a test breakfast meal to which 59Fe had been added. The test meal contained 238 mg calcium. Whole-body countings of 59Fe were performed before and 30 min and 2 wk after each test meal. Retention of 59Fe was 8.3 +/- 1.1% (means +/- SEM) with placebo, 3.4 +/- 0.78% with milk, 6.0 +/- 0.97% with CCM, and 7.4 +/- 1.7% with CCM plus orange juice. When compared with placebo, milk and CCM significantly lowered iron retention (p less than 0.05) whereas CCM plus orange juice did not. The reduction with milk was greater than that with CCM (p less than 0.05) or CCM plus orange juice (p less than 0.05). The differences in the effects of these calcium sources on 59Fe retention may result from their varied contents of citric and ascorbic acids, known enhancers of iron absorption.

The preferential inhibition of Bacillus subtilis spore outgrowth by chloroquine

Chloroquine inhibited the outgrowth of Bacillus subtilis spores at a 10-fold lower concentration than that required to prevent vegetative growth. Analysis of macromolecular synthesis in outgrowing spores and vegetative cells in the presence of chloroquine indicated that it acted preferentially on transcription. Differential sensitivity of outgrowing spores and vegetative cells to chloroquine was not due to changes in the specificity of the RNA-polymerase, since RNA-polymerase activity measured in permeabilized cells was not affected differently by the drug. The preferential inhibition of spore outgrowth was not evident at pH 8.0, at which the majority of chloroquine is in a monovalent, more lipophilic, form. In the presence of inhibitors affecting membrane potential, vegetative cells were as sensitive to chloroquine as outgrowing spores. Measurement of [14C]-chloroquine uptake showed that early outgrowing spores accumulated twice as much drug as resistant late outgrowing spores and seven times more than vegetative cells. Treatment of vegetative cells with metabolic inhibitors led them to accumulate chloroquine to the levels found in outgrowing spores. Therefore, the preferential inhibition of outgrowing spores by chloroquine is the result of increased uptake of the drug, reflecting differences in energy metabolism from vegetative cells.

Amplification of specific DNA sequences in C127 mouse cells transformed by bovine papillomavirus type 4

A rearranged bovine papillomavirus type 4 DNA fragment, present in a line of transformed C127 cells, was molecularly cloned into lambda GT 10. The rearranged viral fragment was found to consist of two separate sequences of 3.8 kb each. Clone A comprised 3.3 kb of host DNA linked to 0.5 kb of BPV-4 DNA. Clone B consisted of 2.2 kb of host DNA linked to 1.5 kb of BPV-4 DNA. The AB locus was found to be amplified and rearranged in a number of different BPV-4 transformed C127 cell lines, irrespective of the presence of viral DNA. The rearranged amplified locus was transferred and maintained in second and third round transformants. We propose that the altered AB locus is involved in the maintenance of the transformed phenotype in the absence of the BPV-4 DNA, and may act as an activated oncogene.

Calcium bioavailability and iron-calcium interaction in orange juice

We have determined the effects of orange juice on calcium bioavailability from CCM (a combination of CaCO3, citric acid, malic acid, 5:1:1, mol/mol/mol) and iron-calcium interaction by using whole body isotope retention techniques in rats. The mean calcium retention values from CCM were 42.8% from orange juice and 33.0% from water, a control. Orange juice significantly (p less than 0.05) improved calcium bioavailability. This enhancement of calcium absorption is independent of orange juice's pH and citric acid. Iron absorption from orange juice with CCM (36.7%) was also significantly higher than that from control (water) plus CCM (12.3%). Ascorbic acid at levels naturally present in orange juice failed to improve iron retention (12.3% vs 12.5%) from water plus CCM. In contrast, citric acid (at orange juice level) significantly (p less than 0.05) promoted iron absorption in the presence of CCM (8.0% vs 23.7%). The benefit of citric acid on iron-calcium interaction is enhanced by ascorbic acid. In the presence of both citric acid and ascorbic acid, at orange juice levels, iron absorption from water plus CCM (37.6%) was comparable to that from water without CCM (34.5%). These results show orange juice can deliver bioavailable calcium from CCM with minimal inhibition of iron absorption. Citric acid and ascorbic acid are likely the major orange juice components that contribute to the alleviation of iron absorption inhibition by CCM.

Meal effects on calcium absorption

The effect of coingestion of a meal on calcium absorption efficiency was investigated using Ca carbonate, milk, and a new Ca delivery system, CCM. Six experiments with 168 rats and two experiments with 46 normal young women showed that coingestion of a light meal of varied composition enhanced absorption efficiency from all three sources by 10-30% above levels achieved when the test load was ingested without other foods. The differences taken as a whole were highly statistically significant.

Aluminum-Induced Calcium Deficiency Syndrome in Declining Red Spruce

Prolonged suppression of cambial growth has apparently caused a decline in radial growth in many mature red spruce, Picea rubens. Surveys indicate that this decline occurs in trees throughout the natural range of red spruce and is independent of elevation, tree size, and age class. In addition, crowns of mature red spruce at high elevations across the northeastern United States have been dying back. Understanding the physiological basis for the growth decline is essential for the judicious management of the red spruce resource. A sequence of events is inferred through which an imbalance of aluminum and calcium in the fine root environment reduces the rate of wood formation, decreases the amount of functional sapwood and live crown, and leaves large trees more vulnerable to extant secondary diseases and insect pests.

"Hit and run" transformation of mouse C127 cells by bovine papillomavirus type 4: the viral DNA is required for the initiation but not for maintenance of the transformed phenotype

Morphological transformation of C127 mouse fibroblasts by bovine papillomavirus type 4 (BPV-4) DNA depends on additional factors, including cell density, the presence of TPA, the concentration of fetal calf serum, and the physical state of the input DNA. Low cell density or the presence of TPA allows the achievement of full transformation, suggesting that disturbance of cell-to-cell contact may be necessary for the expression of the malignant phenotype. TPA also induces a burst of viral DNA synthesis and transcription. The frequency of focus formation is fivefold higher in the presence of high serum than in low serum, indicating that growth factors are required during the early stages of transformation. Although the same number of foci is obtained with either circular or linear DNA, the cells transfected with linear DNA are at a more advanced stage of transformation, being capable of anchorage-independent growth and tumorigenic in nude mice; only 5 out of 21 of these cell lines contain viral DNA in integrated and rearranged forms. In contrast cells transfected with circular DNA are anchorage-dependent but tumorigenic in mice, and do not contain any viral DNA. The linear DNA has an interrupted E1 ORF and fully transformed cells are obtained also with a subgenomic viral DNA fragment containing part of the L1 ORF, the complete E6, E7, and E8 ORFs, and the truncated E1 ORF under the control of the BPV-4 regulatory region; viral DNA is not maintained in any of these cell lines. In total, only 15% of the transformed cell lines contains viral DNA. These results are discussed in the light of the "hit and run" model of cell transformation.

Calcium absorption from a new calcium delivery system (CCM)

Absorption of calcium from a highly soluble form of calcium, a mixed calcium citrate-malate salt (CCM), was tested against calcium carbonate and milk in both rats and humans. The rat method estimated absorption from the 6-day retention of an oral tracer, and the human method employed the standard double-isotope procedure. CCM was given both as a dry powder and in an orange juice beverage. In two experiments in rats calcium from CCM was absorbed at least as well as, if not better than from calcium carbonate or milk. In two separate experiments in humans, calcium from CCM was absorbed significantly better than from calcium carbonate or milk. We conclude that CCM exhibits excellent bioavailability and that this formulation is a useful addition to the forms of calcium now available either for direct supplementation or for food fortification.

The nucleotide sequence and genome organization of bovine papillomavirus type 4

The nucleotide sequence of bovine papillomavirus type 4 (BPV-4) was determined. The viral genome is 7261 base pairs long. Several overlapping open reading frames (ORFs) have been identified both on the basis of amino acid comparison with other papillomaviruses and on their transcriptional pattern. Eight early ORFs (E1 to 8) were recognized, coding for DNA replication and cell transformation functions, and three late ORFs (L1 to 3), coding for structural proteins. Like the E5 ORF of human papillomavirus type 6 the E5 ORF of BPV-4 is discontinuous. Unlike other papillomaviruses, the non-coding region upstream of the early ORFs (ncr-1) is short (385 base pairs), but there is another non-coding region (ncr-2) of nearly 500 base pairs between the L2 and L1 ORFs. Most of the putative regulatory sites are located in the ncr-1, although potential controlling elements are also found in other parts of the genome. Polyadenylation sites are present at the 3' end of both the early and the late transcription units. Comparison between the polypeptides of BPV-4 and other papillomaviruses showed that BPV-4 is evolutionarily closer to the epitheliotropic human and rabbit viruses than to BPV-1.

Transcriptional organization of bovine papillomavirus type 4

Seven virus-specific RNA transcripts have been identified in tumours induced by bovine papillomavirus type 4 (BPV-4). The RNAs measured 4.2, 3.6, 3.0, 2.8, 1.9, 1.6 and 1.0 kilobases (kb). They were mapped on the viral genome by Northern blot hybridization to subgenomic probes, by cDNA hybridization to viral DNA fragments and by S1 analysis of unlabelled and 3' and 5' end-labelled DNA fragments. All the RNA species are transcribed from the same DNA strand, are polyadenylated and with the exception of the 1.0 kb RNA internally spliced. The 3.0, 1.9, 1.6 and 1.0 kb RNAs share the same 3' polyadenylation site at nucleotide 4009 whereas the 4.2 kb RNA and the 2.8 kb RNAs terminate near a polyadenylation site at nucleotide 7187. The 4.2 kb and the 2.8 kb RNAs are transcribed from the late open reading frames and encode the structural polypeptides; the 3.0, 1.9, 1.6 and 1.0 kb RNAs are transcribed from the early open reading frames and are the transcripts involved in viral replication and cellular transformation.

The biology of papillomaviruses and their role in oncogenesis

A large number of different papillomavirus types have been identified. Several viruses often infect the same species and each virus is associated with a defined tissue. Recent evidence has shown that certain benign lesions can undergo malignant transformation in both animals and humans in response to genetic or environmental factors. Fine mapping of the structure and function of the viral genome may enhance our understanding of the interaction between the virus and the cofactors involved in malignant transformation.

Sharpening radiographs

This article describes a method for clarifying and sharpening radiographs. The method uses convolution with a computed tomography reconstruction kernel and a noise elimination procedure to control the noise amplification of the convolution. The effect is to flatten global variations and to sharpen and magnify local variations. Examples from industry and medicine are included.

Papillomavirus research: a growth area

Recent advances in papillomavirus research have revealed a fascinating picture of diversity among viral types, specificity of tissue infected, and oncogenic potential. Fine mapping of the viral functions may prove invaluable in furthering our understanding of the mechanisms of their interaction with, and transformation of, the host cell.

The genomes of bovine papillomaviruses types 3 and 4 are colinear

The 7.2 kb genomic DNA of bovine papillomavirus type 3 (BPV-3) was molecularly cloned using its unique EcoRI site, and the 7.3 kb genome of BPV-4 was cloned using its single BamHI site. The viral genomes were compared by liquid hybridization, Southern blot hybridization and heteroduplex mapping. Low stringency hybridization conditions revealed that the genomes are colinear but the sequences are extensively mismatched. The relative alignment of the restriction endonuclease maps of the two viral genomes has been determined. It was found that the genomes as linearized for cloning are out of phase by 1.7 kb, so that the single EcoRI site of BPV-3 appears to coincide with the BPV-4 EcoRI site at 0.22 map units. It is concluded that the genomes of BPV-3 and BPV-4, both of which cause true epithelial warts, share the same physical organization but exhibit sequence divergence.

Community cooperation among a university, a community college, a hospital, and a high school: a new model for allied health education

The University of Texas Health Science Center at Dallas, School of Allied Health Sciences, has designed and established a linkage plan that could help solve the health personnel shortages in many cities. This plan joins several schools to (1) stimulate the implementation of programs to provide limited numbers of trained health professionals, (2) establish a coordinated system whereby technologists and technicians can be trained, (3) prepare qualified persons to staff the local hospitals, and (4) provide a ladder for advancing motivated and qualified health professionals. Coordination of efforts among the university, the seven-member Dallas Community College District, and the Dallas Independent School District's High School for Health Professions facilitates solid academic instruction at these institutions, which is followed by well-supervised clinical experiences in the local hospitals under highly qualified professionals. To date, the program includes the education of nuclear medicine technologists, radiation therapy technologists, electroencephalographic technologists, and histologic technicians. This mode of education is one solution to the health professional shortage.

Zinc-binding properties of bovine and human milk in vitro: influence of changes in zinc content

The total zinc content of samples of fat-free human and bovine milk was 3.5 and 3.6 micrograms/ml, respectively. The total protein content was 5.3 and 29.0 mg/ml, respectively, Sephadex G-75 gel filtration chromatography of bovine milk revealed no evidence of zinc associated with low molecular weight fractions (less than 2000 daltons). However, chromatography revealed that 10% of the zinc in human milk was associated with these fractions. When the zinc content of these milks was raised by adding Zn2+ in vitro, chromatography of milk from both species revealed the presence of zinc with the low molecular weight fractions. More zinc was associated with these fractions from human milk than from bovine milk. Recovery of zinc was nearly 100% for all columns. It is proposed, based upon these binding data, that the association of zinc with low molecular weight components of milk is related in part to both protein content and composition and the relative zinc concentrations. These binding differences might influence the bioavailability of zinc from milk.

Quantitative aspects of zinc absorption by isolated, vascularly perfused rat intestine

Quantitative measurements of zinc absorption were made using the isolated, vascularly perfused rat intestine as a model. The perfused intestine retains the ability to discriminate between absorption processes for calciu, copper, iron and zinc. Measurements of zinc absorption by the perfused intestine, using atomic absorption spectrophotometry, indicated the presence of a zinc pool within intestinal mucosal cells. The zinc concentration in the lumen of the perfused intestine was directly related to the amount of zinc that appeared in the vascular perfusate. Intestines obtained from zinc-deficient animals exhibited an ability to process greater quantities of zinc which resulted in enhanced absorption. The maximal rate of zinc absorption was 229 nmoles per hour with intestines from rats fed adequate amounts of zinc and 627 nmoles per hour when a zinc-deficient diet was fed. Administration of zinc to rats before isolation and perfusion of the intestine resulted in greater intracellular retention of zinc taken up from the lumen and correspondingly lesser amounts (75 nmoles per hour) transferred to the vascular supply. These data provide quantitative evidence that the perfused intestine retains its ability to exercise homeostatic control over the zinc absorption process and that the intestinal cell is a major site of regulation.

Identification of albumin as the plasma carrier for zinc absorption by perfused rat intestine

The isolated vascularly perfused rat intestine exhibits an obligatory need for a protein carrier in order to absorb zinc. Therefore this system is ideal for use as a model to identify the plasma carrier during zinc absorption. Affinity chromatography on Blue Sepharose CL-6B was employed to separate the major serum zinc-binding proteins in the portal effluent of the perfused intestine. It was found that 94% of newly absorbed 65Zn was transported in the portal serum-containing perfusate as an albumin-65Zn complex. The identity of albumin as the plasma carrier was confirmed by polyacrylamide-slab-gel electrophoresis. This evidence suggests that albumin is the plasma protein that is involved in removal of zinc from intestinal-mucosal cells and subsequent transport of the metal in portal blood to the liver.

Zinc absorption and metabolism by isolated, vascularly perfused rat intestine

An isolated vascularly perfused rat intestine system was utilized to examine various aspects of zinc absorption in an attempt to more clearly examine the mechanisms involved. The lumen was perfused with a modified tissue culture medium containing 65Zn. The vascular system was perfused from the superior mesenteric artery to the portal vein, with Krebs-Ringer bicarbonate buffer containing 5% rat serum. The criterion for absorption was the amount of radioactivity transferred to the vascular perfusate. When the intestines were obtained from rats that had consumed a zinc-deficient diet the amount of zinc absorbed increased markedly. Conversely, elevation of zinc status decreased the amount of 65Zn that could be transferred to the vascular perfusate. These data strongly suggest that the isolated, perfused rat intestine retains the ability to exercise homeostatic control over 65Zn absorption. Transfer of infused 65Zn to the vascular perfusate was significantly decreased by aspirin, phytate, and prostaglandin E2. Uptake of 65Zn from the lumen into the intestinal cells was significantly increased by histidine and significantly decreased by phytate and prostaglandin E2. Thus, the isolated, vascularly perfused rat intestine appears to be capable of differentiating between the cellular uptake and cell to plasma transfer phases of zinc absorption.

Coordinate and non-coordinate accululation of aspartate transcarbamylase and dihydroorotase in synchronous Chlorella cells growing on different nitrogen sources

Regulation of the levels of aspartate transcarbamylase (carbamoylphosphate:L-aspartate carbamoyltransferase, EC 2.1.3.2) and dihydroorotase (L-5,6-dihydro-orotate amidohydrolase, EC 3.5.2.3) was studied in synchronous cultures of the eucaryotic microorganism Chlorella. Analytical polyacrylamide gel electrophoresis and sucrose density-gradient centrifugation studies revealed that these cells contain a single aspartate transcarbamylase and a dihydroorotase with apparent molecular weights of 160 000 and 80 000, respectively. In synchronous cells cultured in nitrate medium, these two enzymes accumulated in single step-patterns over different periods of the cell cycle. In contrast, these enzymes accumulated in a coordinate manner throughout the cell cycle in ammonium medium. Experiments with inhibitors of protein and RNA synthesis indicated that dihydroorotase is stable in vivo and suggested that cell cycle changes in the turnover rate of aspartate transcarbamylase might determine whether or not these enzymes accumulate in a coordinate manner. Although uracil and uridine could be absorbed and metabolized by the cells, synthesis of these two enzymes could not be repressed by culturing synchronous cells in medium, containing high concentrations (29-40 mM) of uracil or uridine, for an entire cell cycle.

The diagnosis of breast cancer in mammograms by the evaluation of density patterns

Standard mammograms from 33 patients with surgically proved adenocarcinoma or fibrocystic disease were analyzed with a scanning microdensitometer and computer. A quickly computable number called the linear mass ratio is introduced. This simple ratio discriminated correctly between the 16 adenocarcinomas and 17 fibrocystic lesions of the study, all cases in which diagnosis had required biopsy.

Reconstruction of objects from radiographs and the location of brain tumors

The objective of this research is two-fold: (i) the development of a method for locating hemorrhages, blood clots, and tumors in the brain by means of ordinary hospital radiographs and without the introduction of contrast material; and (ii) the uncovering of new mathematical results through this point of view. The present note deals mainly with the first objective, but the mathematical setting and convergence and indeterminacy theorems are also described.

Homophobia: a tentative personality profile

The study of homosexuals only is insufficient to understanding homosexual problems. Research was conducted to investigate individuals whose negative attitude toward homosexuals may contribute to the problem. A tentative profile suggests these individuals may be status conscious, authoritarian and sexually rigid. Other aspects of their personalities are discussed and subsequent research is outlined.