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Biomedical subjects

G Grant

Publications and source records attributed to G Grant.

At least 145 records · Page 8Linked to original sources
PubMed1991

National survey of clinical and subclinical mastitis in Jamaican dairy herds, 1985-1986.

Between April 1985 and August 1986, 89 Jamaican dairy herds with 10 or more cows were visited, 1,645 lactating cows were examined using the CMT test and 254 composite milk samples collected for bacteriological examination. Widespread management faults were noted, especially of milking machine usage and maintenance and the abuse of antibiotics. Fifty-six per cent of all quarters were found to have CMT scores of one or higher, 0.8% showed clinical mastitis and 3.2% were blind. The most common bacterial pathogen Staphylococcus aureus, was recovered from 31% of sampled cows. The resultant milk loss from clinical and subclinical mastitis was estimated to be 20% of the potential national production.

Animals↗
PubMed1991

Nutritional response of growing rats to faba beans (Vicia faba L., minor) and faba bean fractions.

The effects of raw faba bean (Vicia faba L., minor) meal (VFM) and its fractions on the growth and nitrogen utilization of rats have been determined in two experiments. Two commercial varieties of VFM were tested, local VFM (409-439 g/kg diet) and Troy VFM (439 g/kg diet). The bean fractions tested were V. faba lectin-depleted protein (VFDP), V. faba lectin (VFL) and V. faba cotyledon residue (VFCR). All diets were supplemented with amino acids to target requirements. Body-weight, body N and lipid contents of rats fed on VFM were reduced significantly in comparison with control rats fed on lactalbumin. This was due, in part, to the lower digestibility of the protein, lipid and dry matter (DM) of VFM diets. As a result, net protein utilization (NPU) and biological value (BV) of faba bean proteins were less than expected. Urine and urea-N outputs of the VFM-fed rats were also elevated in both experiments. Increasing the energy content of local VFM diets led to significantly higher dry body-weight, body N and lipid contents, with the result that the NPU and BV values of the protein also increased. However, the NPU values for VFM-fed rats were still significantly lower than those for the controls in both experiments. In contrast, true N, lipid and DM digestibilities in rats given local VFM were not significantly affected by the difference in the energy content of the diets. The replacement of two-thirds of the lactalbumin in the diet with VFDP (65 g/kg) reduced dry body-weight, N and lipid contents, NPU and BV compared with the control rats, even though N, lipid and DM digestibilities were not significantly different. The nutritional performance of rats fed on lactalbumin-based diets containing 7 g VFL/kg was similar to that of the controls. Similarly, the inclusion of the cotyledon residue (237 g VFCR/kg diet) had no appreciable effect on any of the variables studied. As VFL and VFCR had no antinutritional effects in these rats, it appears that the low nutritional value of VFM for rats (NPU 0.66) results not only from the low digestibility of the bean proteins, but also from disturbances in N metabolism.

Animals↗
PubMed1991

Tolerance of the eye for implanted cilia.

Retained cilia in the eye following injury are rare. There are reports of long term tolerance to cilia in the anterior chamber but no information about the effect on the corneal endothelium. A 31-year-old man was seen with a 19-year history of a retained eyelash embedded in a corneal scar and extending across the anterior chamber to the chamber angle. The follicle was absent. There was no cellular inflammatory reaction, and the eye otherwise appeared normal on slit-lamp examination with normal vision. However, there was the appearance of an encrusted deposit on the surface of the lash and a markedly lowered endothelial cell count of 750 cells/mm2 compared with the fellow eye. The lash was not removed.

Adult↗
PubMed1991

Effect of fasting and refeeding on basolateral polyamine uptake and metabolism by the rat small bowel.

Fasting reduced the weight, protein, DNA, RNA and polyamine contents of the small intestine of rats, but its effects on the in vivo uptake of intraperitoneally injected 14C-spermidine through the basolateral membrane of the small intestine were small. The uptake of putrescine was nearly doubled by fasting for 48 h. Fasting for 48 h had reduced villus length but was without effects on the crypts. Refeeding for 6 h of rats fasted for 48 h led to hypertrophic growth: the length of both crypts and villi increased by about 50% without changes in cell number. The uptake of spermidine by the small intestine increased above not only that in fasted rats but also that in the controls fed ad libitum. The high putrescine uptake of rats fasted for 48 h was unchanged after refeeding for 6 h, but returned to control values after 12 h. Spermidine in the gut was well conserved, while most of the putrescine was transformed into non-polyamine metabolites. It is concluded that refeeding stimulates basolateral spermidine uptake, and this may be a general mechanism for polyamine accretion in adaptive growth of the small intestine.

Animals↗
PubMed1990

Spontaneous abnormalities in normal fibroblasts from patients with Li-Fraumeni cancer syndrome: aneuploidy and immortalization.

Families of patients with the Li-Fraumeni cancer syndrome have an inherited pattern of sarcomas and various other types of cancers that follow a dominant mode of transmission, an early age of onset, and exhibit multiple primary tumors. As soft tissue sarcomas (including fibrosarcomas) are frequently observed with this syndrome, the in vitro growth characteristics of fibroblasts derived from skin biopsies of Li-Fraumeni syndrome patients were studied. Control fibroblasts maintained a normal morphology and eventually senesced in culture. Fibroblasts from seven of eight affected individuals developed changes in morphology, anchorage-independent growth, and chromosomal abnormalities. In a fashion similar to that of fibroblasts from normal donors they underwent a growth crisis during which their growth was slow, but they continued to grow past the point at which control samples had stopped dividing (35 population doublings). Fibroblasts from Li-Fraumeni cancer patients escape senescence, growing well beyond 35 population doublings with growth rates similar to early-passage cells. Patient fibroblasts maintain the morphology of a transformed cell but remain nontumorigenic in nude mice. These observations of the behavior of fibroblasts from patients with the Li-Fraumeni syndrome may have predictive value for the determination of gene carriers within these families who are at high risk of cancer.

Aneuploidy↗
PubMed1990

Distribution of lumbar dorsal root fibers in the lower thoracic and lumbosacral spinal cord of the rat studied with choleragenoid horseradish peroxidase conjugate.

Spinal cord projections from lumbar dorsal root ganglia (DRGs) were investigated in adult rats following injections of choleragenoid horseradish peroxidase (B-HRP) into each of the six lumbar DRGs. This method is known to label primarily thick fibers. Labeling was found in all laminae except in the outer part of lamina II. Labeled fibers and terminal-like structures were found 8-13 segments rostral and 1-5 segments caudal to the injected DRGs. A somatotopic organization was revealed in laminae III, where the labeling seemed to be organized in mediolateral zones. Some of these protruded as fingerlike processes through segments rostral and caudal to the root entry level. An interdigitating pattern for these fingerlike processes was seen between some DRGs, while an extensive overlap was found between other DRGs. Many zones were found to correspond to the known central projections of peripheral sensory nerves supplied by the injected ganglion. This suggests that the central projection of a DRG is highly related to the projections of the peripheral nerves included in the DRG. The projections to lamina IV were organized in a similar manner as in lamina III, even though the projections showed a higher degree of overlap than in lamina III. No clear somatotopic organization was found in laminae V-IX. Provided that the topographical relationship between central projections of single peripheral nerves and of DRGs correspond to their peripheral projections, the results of this study, together with results of earlier studies suggest that the outlines of dermatomes are highly related to the territories of peripheral nerves included in the dermatomes.

Animals↗
PubMed1990

Luminal and basolateral polyamine uptake by rat small intestine stimulated to grow by Phaseolus vulgaris lectin phytohaemagglutinin in vivo.

Luminal and basolateral uptake of polyamines by the rat small intestine was studied in vivo. In the concentration range studied (0.1-5 mg per rat) 23-47% of the individual polyamines given intragastrically were found in the body after 1 h, with the small intestine retaining 4-12% of the dose. With spermidine or spermine, labelled polyamines accounted for 85-96% of the counts in the small intestine and between 72-82% were in the form given. However, with putrescine only 29-39% of the label found in the tissue remained in polyamine form and even less, 11-15%, as putrescine. Luminal uptake of polyamines was linear, non-saturable and was not stimulated when small intestinal growth was stimulated by phytohaemagglutinin (PHA). On the basolateral side of the gut, polyamine uptake was stimulated by PHA in a time-dependent way in advance of detectable growth. Overall polyamine recoveries were high (89-99%) with intraperitoneally administered spermidine and spermine. Moreover, a large proportion of the counts in the tissue (63-89%) were still in the original form. Even with putrescine, total recoveries of polyamines (72-88%) and putrescine (24-33%) were elevated in comparison with those from the lumen. Treatment of rats with alpha-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase, reduced tissue polyamine content, although it had slight effects only on basolateral polyamine transport. The PHA-stimulated increase of polyamine uptake was not abolished in the presence of DFMO.

Animals↗
PubMed1990

Lumbar dorsal root projections to spinocerebellar cell groups in the rat spinal cord: a double labeling study.

The aim of this study has been to investigate projections to spinocerebellar cell groups from lumbar dorsal root ganglia (DRGs) in the rat. The binding subunit of cholera toxin conjugated to horseradish peroxidase (B-HRP) was used to label primary afferent fibers. Spinocerebellar neurons were labeled retrogradely by Fluoro-Gold (FG). To determine the orientation of dendrites, retrogradely labeled spinocerebellar neurons were studied, following injections of wheat germ agglutinin conjugated horseradish peroxidase (WGA-HRP) into cerebellum. FG or WGA-HRP labeled neurons were found mainly in laminae V and VII, in the lateral group of lamina IX, in Clarke's column (CC) and in the dorsal funiculus. B-HRP labeled primary afferent fibers overlapping with FG labeled cells were observed at all these locations after injections of B-HRP into different DRGs. The overlap in lamina V was found mainly medially and dorsolaterally. CC was found to receive dense projections from DRGs L1-6. In the lumbar part of CC, labeling from DRGs L4-5 overlapped and was distributed over the entire mediolateral extent of the CC, whereas labeling from DRGs L1-3 was somatotopically organized and projected to successively more dorsomedial areas. The central area of lamina VII showed moderate labeling from DRGs L3-5. The lateral group of lamina IX received only smaller amounts of labeled fibers from DRGs L3-5.

Animals↗
PubMed1990

A reappraisal of the Malaise Inventory.

In recent years Rutter's Malaise Inventory has been used increasingly to measure levels of stress among those who care for people with dependency needs. Although there has been an element of dispute in the literature about the unidimensional nature of the scale, later work (Bebbington and Quine 1987) tends to suggest that Malaise Inventory scores can be used as a single internally consistent measure of stress. In this study consideration is given to the results of a national sample survey of 527 members of the Association of Carers (now Carers: National Association) which suggests the existence of two valid dimensions to the Malaise Inventory across a wider range of carer groups. Implications for future development and administration of the scale as a measure of stress are discussed.

Chronic Disease↗
PubMed1990

Ultrastructural changes of the central scalloped (C1) primary afferent endings of synaptic glomeruli in the substantia gelatinosa Rolandi of the rat after peripheral neurotomy.

Fine structural changes were observed in the dark scalloped central C1 terminals of type I synaptic glomeruli in spinal cord segments C6-C7 of the rat 3 days after cutting the three main forelimb nerves. Twenty-six per cent of the C1 terminals occurring on the ipsilateral side showed a lighter appearance due to a decrease in the number of synaptic vesicles. The number of synaptic vesicles per unit section area was only 42% of that present in normal C1 terminals on the contralateral side. The number of synaptic contacts of C1 terminals with the profiles surrounding them in each glomerulus was diminished and glial envelopment was increased to 15% of C1 terminal contour. Up to day 12, vesicle and synaptic losses were gradually aggravated and glial apposition was increased, but no obvious signs of glial engulfment were observed. From day 3 to day 12, altered C1 terminals increased in number, while those that appeared normal decreased. The latter had disappeared at day 12 and the altered ones at day 15, and from this stage type I glomeruli were no longer present on the treated side. The lack of electron-dense degenerative bouton changes characteristic of Wallerian degeneration offers an explanation for the lack of or minimal amount of argyrophilic structures which has been found consistently in the substantia gelatinosa during transganglionic degeneration. The gradual decay of the C1 terminals raises the question of their fate. Future studies with the use of a stable marker might provide an answer.

Afferent Pathways↗
PubMed1990

Serological survey for leptospiral antibodies in goats in St Elizabeth Parish, Jamaica, 1985-1986.

A serological survey of goats in St Elizabeth Parish, Jamaica, comprising the breeding herd at the Agricultural Development Corporation (ADC) facility at Hounslow, five commercial herds and 21 family herds was carried out in 1985-1986. The Leptospira microscopic agglutination test indicated that one or more serovars in the Canicola serogroup were the most prevalent. Repeated samplings of goats at ADC, Hounslow demonstrated an increase in portlandvere and canicola seropositive animals following the onset of warmer weather and of icterohaemorrhagiae seropositive animals following the autumn rains and cooler weather. Apart from a cluster of family goats seropositive to pomona there was no geographical separation of reactors to the other serovars tested in the parish.

Agglutination Tests↗
PubMed1990

Comparison of specular microscopy and examination of aspirate in phacolytic glaucoma.

Although phacolytic glaucoma is well known and the clinical picture is well recognized, the nature of the polychromatic hyperrefringent granules is less well understood. A series of five cases was examined by specular microscopy, and the anterior chamber aspirate obtained at operation was subsequently examined by direct microscopy of the wet aspirate. Direct microscopy showed that the macrophages identified histologically in the aspirate corresponded to regular round cells about three times the size of an erythrocyte seen in the relief mode of specular microscopy. This finding aided in the interpretation of cellular deposits seen on specular microscopy. One hyperrefringent granule was seen on the posterior endothelium on specular microscopy, and results of subsequent examination of the aspirate showed this and the crystals in another patient to be morphologically identical with cholesterol crystals. The findings confirm that cholesterol crystals are present in the exudate in phacolytic glaucoma and are responsible for hyperrefrigent granules.

Adult↗
PubMed1990

Stress is in the eye of the beholder: reconceptualizing the measurement of carer burden.

The development of community care policy and the inadequacies of professional responses to the needs of informal carers were described in an earlier paper. A qualitative analysis of carers' replies to a questionnaire survey demonstrated that the most potent stressors, contrary to what has previously been assumed, were linked more to subjective perceptions of events or circumstances than to the objective features of the events and circumstances themselves. This paper presents a quantitative analysis of data from the same survey which confirm the impressions gained from the analysis of the qualitative data. These findings prompt a reconceptualization of carer burden within a transactional model of stress, which is then considered as a basis for understanding how carers adapt to stress in their lives. Practice implications are assessed.

Activities of Daily Living↗
PubMed1990

Relationship between survival and binding of plant lectins during small intestinal passage and their effectiveness as growth factors.

The effects on the small intestine and the growth of rats of six pure plant lectins: PHA (Phaseolus vulgaris); SBL (Glycine maxima); SNA-I and SNA-II (Sambucus nigra); GNA (Galanthus nivalis) and VFL (Vicia faba), covering most sugar specificities found in nature, were studied in vivo. Variable amounts, 25% (VFL) to 100% (PHA, GNA) of the lectins administered intragastrically, remained in immunochemically intact form in the small intestine after 1 h. All lectins, except GNA, showed binding to the brush border on first exposure, although this was slight with VFL. Thus, binding to the gut wall was not obligatory for resistance to proteolysis. Exposure of rats to lectins, except VFL, for 10 days, retarded their growth but induced hyperplastic growth of their small intestine. The two activities were directly related. PHA and SNA-II, whose intestinal binding and endocytosis was appreciable after 10 days of feeding the rats with diets containing these lectins and similar to that found on acute (1 h) exposure, were powerful growth factors for the small intestine. GNA, which did not bind at the start but was reactive after 10 days, and SNA-I, which behaved in the opposite way, induced changes in receptor expression in the gut. As they were bound to the brush border transiently, they were less effective growth factors. VFL was not bound or endocytosed, was non-toxic and did not promote gut growth.

Animals↗
PubMed1990

Polyamine metabolism and uptake during Phaseolus vulgaris lectin, PHA-induced growth of rat small intestine.

Kidney bean lectin, PHA, stimulated the hyperplastic and hypertrophic growth of rat small intestine. This growth was preceded by a rapid accumulation of polyamines in the small intestine. However, since the lectin had little effect on in situ polyamine biosynthesis, most of the polyamines must have been of extracellular origin. To investigate the source of polyamines, both the luminal uptake and basolateral transport of polyamines by the rat small intestine were measured in vivo. Luminal polyamine uptake was apparently by passive diffusion, non-saturable, linearly dependent on concentration and its extent was not stimulated by PHA. In contrast, 14C-polyamines injected intraperitoneally were probably taken up by a transport system(s). Moreover, basolateral polyamine transport was stimulated in a time-dependent manner when small intestinal growth was stimulated by PHA. However, in keeping with the finding of polyamine accumulation prior to demonstrable growth of the tissue, stimulation by PHA of the polyamine transport system also preceded small intestinal growth. Stimulation of polyamine transport by luminal factors is possibly a general mechanism involved in intestinal adaptation.

Adaptation, Physiological↗
PubMed1990

Determinants of smooth muscle injury during balloon angioplasty.

To study the determinants of smooth muscle injury during balloon angioplasty, we conducted a series of experiments to examine the effects of degree of arterial stretching, duration of balloon inflation, and arterial precontraction on smooth muscle injury after balloon angioplasty in isolated, perfused whole-vessel segments of rabbit aortas and dog carotid arteries. Freshly dissected rabbit thoracic aortas and dog carotid arteries were mounted in a muscle bath-perfusion chamber and perfused at 80 mm Hg. The proximal half of each aorta was dilated with a 5-mm (41 +/- 6% stretch), 6-mm (64 +/- 6% stretch), or 8-mm (97 +/- 9% stretch) balloon angioplasty catheter, and the uninjured half of each vessel served as the control. The vasoconstrictor behavior of the dilated segment was then assessed by dose-response testing; long-axis, ultrasonic imaging combined with computerized edge-detection image processing was used to measure changes in segmental internal vessel diameters that were induced by phenylephrine. A similar series of experiments was performed in dog carotid arteries with 5-mm balloon catheters (42 +/- 2% stretch) to compare the susceptibility to smooth muscle injury between elastic (aortic) and muscular (carotid) arteries. Additional experiments were performed to determine the roles of prolonged (30 minutes) balloon inflation and arterial precontraction on smooth muscle injury after balloon angioplasty. In rabbit aortas, the dilated arterial segments demonstrated normal reactivity to phenylephrine after dilatation with 5- and 6-mm balloons (p = NS versus control). Severe smooth muscle injury (histopathologically) with "arterial paralysis" was observed after severe stretch (8-mm balloon) and after 5-mm balloon dilatation (46 +/- 5% stretch) in precontracted vessels. Prolonged balloon inflations did not impair aortic vasoconstrictor behavior. Dog carotid (muscular) arteries demonstrated angioplasty-induced smooth muscle injury with less severe degrees of stretch (47-52% stretch). Geometric modeling suggests that medial stretching during balloon angioplasty of diseased vessels in vivo is in the range of 15-41%.(ABSTRACT TRUNCATED AT 400 WORDS)

Angioplasty, Balloon↗
PubMed1990

A restriction fragment length polymorphism for human topoisomerase II: possible relationship to drug-resistance.

In previous studies we used Southern blotting to examine the topoisomerase II locus (on chromosome 17) in human leukemia cell lines and noted a difference in the XmnI restriction endonuclease digestion pattern between an m-AMSA-resistant line and its m-AMSA-sensitive parent line (Zwelling, L. A.; Hinds, M,; Chan, D.; Mayes, J.; Sie, K. L.; Parker, E.; Silberman, L.; Radcliffe, A.; Beran, M.; Blick, M. Characterization of an amsacrine-resistant line of human leukemia cells. Evidence for a drug-resistant form of topoisomerase II. Journal of Biological Chemistry 264:16411-16420; 1989). We now demonstrate that the variable XmnI digestion pattern represents a normal restriction fragment length polymorphism (RFLP) which is observed in subjects without malignant disease and exhibits an autosomal pattern of inheritance. These data suggest that the previously described deviation in the genomic structure of topoisomerase II in the m-AMSA-resistant cell line did not reflect a new mutation, but rather a reduction to homozygosity at the topoisomerase II locus. This reduction to homozygosity is not due to chromosomal loss, as chromosome 17-specific gene probes clearly identify two chromosome 17's in the sensitive line and four in the resistant line, using chromosome painting with a chromosome 17-specific library. Some other genetic change must be the cause of the resistance of HL-60/AMSA and its topoisomerase II to the inhibiting actions of m-AMSA.

Alleles↗