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Biomedical subjects

S Lloyd

Publications and source records attributed to S Lloyd.

At least 127 records · Page 7Linked to original sources
PubMed1992

Cytosolic calcium and insulin resistance in elderly patients with essential hypertension.

We evaluated insulin sensitivity in normotensive (blood pressure, BP, less than 135/85 mm Hg) and hypertensive (BP greater than 160/90 mm Hg) elderly subjects over 65 years old who were stratified as normal weight (body mass index, BMI, less than 27) and obese (BMI greater than 27). Obese hypertensive individuals demonstrated marked hyperinsulinemia (P less than .01) and significantly reduced (P less than .05) submaximally stimulated adipocyte 2-deoxyglucose (2-DOG) uptake (abdominal wall fat biopsy). Normal weight hypertensive subjects also demonstrated higher levels of insulinemia and lower insulin-stimulated 2-DOG uptake than nonobese controls. Adipocyte [Ca2+]i levels were elevated in all elderly subjects compared to young individuals (P less than .01). Basal and maximally stimulated 2-DOG uptake were similar in all groups. One month of therapy with a calcium channel blocker, 10 mg nitrendipine twice daily, reduced blood pressure in the hypertensive subjects, reduced plasma insulin to control values during an oral glucose tolerance test in obese hypertensive individuals (P less than .01), and restored adipocyte 2-DOG uptake at submaximally effective insulin concentration to control values in normal weight and obese hypertensive subjects. In summary, older hypertensive, and particularly older obese hypertensive, patients manifest significant insulin resistance accompanied by elevated levels of [Ca2+]i in their adipocytes.

Adipose Tissue↗
PubMed1992

Casemix and costing hospital information program, Brisbane South Regional Health Authority: a preliminary study to determine the emergency department component of DRG costs.

The issue of costs incurred for patients in the Emergency Department who are subsequently admitted was investigated by the authors to determine the significance of costs and to identify which DRGs and clinical specialties are likely to be affected. A theoretical costing study was performed in collaboration with the staff in the Emergency Department for patients admitted through this Department. The Study was a preliminary one with a number of methodological limitations. This paper describes how the costing exercise was performed. The DRGs most likely to be admitted via this route are identified and recommendations for further study are made. The study results identify a number of issues that require resolution prior to the introduction of casemix based funding.

Cost Allocation↗
PubMed1992

Lymphocyte reactivity to antigens of Haemonchus contortus in antigen-inoculated and H contortus-naive lambs.

Lambs were inoculated during either fetal or early neonatal life with antigens of Haemonchus contortus (HcAg) third-stage larvae, or ovalbumin (OVA), or were left untreated. By the time lambs were 4 weeks old, blood lymphocytes from all of them responded to HcAg. This was evident in all lambs, regardless of the previous inoculation regimen, although higher response was seen in HcAg-inoculated lambs, compared with naive lambs. Only lambs inoculated with OVA had OVA-specific lymphocyte activity. In HcAg-naive lambs, the maximal HcAg lymphocyte response was observed between the ages of 5 and 25 weeks, with gradual decrease thereafter. In vitro detection of HcAg-reactive lymphocytes was affected by antigen concentration and presence of plasma. Plasma inhibited HcAg-reactive lymphocytes from all lambs at high in vitro antigen concentration and completely abrogated the response in H contortus antigen-naive lambs.

Animals↗
PubMed1992

Efficacy of a drug combination of praziquantel, pyrantel embonate, and febantel against helminth infections in dogs.

Tablets containing praziquantel, pyrantel embonate, and febantel were tested for efficacy against helminths in dogs. A single treatment with this drug combination gave 100% reductions in Toxocara canis and Taenia hydatigena in experimentally induced infections in dogs. In dogs with naturally acquired infections, treatment gave > 97 to 98% reductions in fecal egg counts attributable to Toxascaris leonina, T canis, and Uncinaria stenocephala. Efficacy against Trichuris vulpis was > 92%.

Animals↗
PubMed1992

Collection of eggs and hatching and culturing second-stage larvae of Toxocara vitulorum in vitro.

Eggs of Toxocara vitulorum were harvested from the feces of infected buffalo calves and embryonated in vitro. Optimum conditions for hatch and culture of the second-stage larvae were determined. Maximum hatch of larvae occurred from eggs that were decoated by treatment with saturated Ca(OCl)2 for 16-24 min followed by treatment with CO2 and incubation at 37 C. Larvae could be cultured in RPMI-1640 medium for up to 3 mo but survived for only 3 wk in Eagle's minimum essential medium.

Animals↗
PubMed1992

Women's work?

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Adult↗
PubMed1991

Use of sentinel lambs for early monitoring of the South Powys Hydatidosis Control Scheme: prevalence of Echinococcus granulosus and some other helminths.

Sentinel lambs were used to identify young Echinococcus granulosus infections in sheep, to provide an early indication of the progress of the South Powys Hydatidosis Control Scheme. Four sentinel lambs were purchased on each of 60 farms, from inside and outside the control area; they were examined when approximately six, 10 and 15 months of age. Gross examination, thin slicing of organs and histological examination of the lesions in the viscera revealed no E granulosus hydatid cysts in lambs born within the control area, whereas 25 per cent of the 15-month-old lambs from outside the area harboured E granulosus cysts (less than 1 to 2 mm in diameter). Lambs from E granulosus infected farms had significantly higher anti-E granulosus ELISA antibody titres than lambs from uninfected farms. It was concluded that within one year of beginning to treat dogs with praziquantel every six weeks the transmission of E granulosus to sheep had ceased. In contrast, this treatment did not prevent infections with Taenia hydatigena or T ovis; an examination of the 240 lambs revealed T hydatigena in 33.3 per cent of them, Tovis in 4.2 per cent, Dictyocaulus filaria in 12.1 per cent and Meullerius capillaris in 49.2 per cent.

Animals↗
PubMed1991

Intestinal changes in puppies infected with Toxocara canis.

Small intestinal histopathology and absorption were examined in Beagle puppies infected with either a moderate or a low burden of Toxocara canis. Infection with T. canis significantly reduced absorption of xylose, but only slightly delayed absorption of para-aminobenzoic acid. Fat assimilation was reduced and faecal proteolytic activity was increased. A significant reduction in villous height occurred and was inversely related to the extent of the infection. Villous goblet cell numbers, particularly those in the luminal third of the villus, were lowest and crypt goblet cell numbers were highest in the most heavily infected of the puppies. Villous goblet cell numbers increased rapidly after treatment of the puppies with piperazine or after the spontaneous elimination of the T. canis infection while crypt goblet cell numbers were less affected by elimination of the parasites. Intra-epithelial lymphocyte numbers were lowest in 33- to 37-day-old puppies infected with greater than 127 T. canis and highest in 44- to 46-day-old puppies losing their infection. Infection with T. canis had no apparent effect on mast cell numbers or pyroninophilic cell numbers in the lamina propria.

4-Aminobenzoic Acid↗
PubMed1991

The effects of sleep posture and sleep stage on apnea frequency.

The Apnea Plus Hypopnea Index (A + HI) of 60 male positional sleep apneics was analyzed by sleep stage to determine if positional differences are limited to NREM sleep. Differences in apnea severity by sleep position were found to persist in REM sleep and to be of equal extent to those differences found in NREM sleep, despite the fact that there is also a significant increase in the frequency of apneic events associated with REM sleep. The positional effect persists in REM sleep, making treatments to control sleep posture a viable option.

Adult↗
PubMed1991

Nonpharmacologic treatment of periodic leg movements in sleep.

The effects of a 30-minute stimulation of the dorsiflexors of the feet and toes before bedtime were investigated in eight patients with periodic leg movements in sleep (PLMS). None were taking medications at the time of the investigation. All subjects were treated with the EMS-250 Neuromuscular Stimulator, which has a maximum output per channel of 1.5mA and a frequency of 47Hz. Stimuli were delivered via a pulse train (on for 1.5sec and off for 1.8sec). A single all-night polysomnogram after this stimulation showed that all patients responded to stimulation, with reduction of leg movements from an average pretreatment PLMS index of 44.6 per hour to a posttreatment PLMS index of 14 per hour (p less than .01). Nocturnal leg movements were primarily reduced during the non-REM sleep. Multiple indices of sleep continuity did not change significantly, although there was a trend toward better sleep consolidation.

Adult↗
PubMed1990

Opposing effects of vasopressin on matching versus non-matching to position: further evidence for response, not memory, modulation.

Rats were trained on either of two related variants of an operant memory task. In the matching to position (MTP) task, one of two retractable response levers appeared, at random, as the sample. A response caused the lever to retract and this was followed by a delay (0-32 s) interval, during which the subjects had to approach and respond at the magazine tray. Both levers were then presented and the rat had to respond, for food reward, to the one which had appeared as the sample. A second group of rats learned non-matching to position (NMTP). This task was very similar to MTP, with one crucial difference: here, the subject had to respond to the lever which had not appeared as the sample. Both groups of rats learned their respective tasks rapidly, performance depending on the delay interval as expected. They were then injected, peripherally, with different doses of arginine-vasopressin (AVP: 0-25 micrograms/kg), a peptide which others have argued improves mnemonic performance. There was evidence to suggest that MTP performance was improved by AVP; on the other hand, NMTP performance appeared to be disrupted. It is suggested that AVP induces a bias towards responding on one side of the two lever test chamber. In other words, it affects motor or motivational, not mnemonic mechanisms.

Animals↗
PubMed1990

Memory following cholinergic (NBM) and noradrenergic (DNAB) lesions made singly or in combination: potentiation of disruption by scopolamine.

Groups of rats were trained on either delayed matching or nonmatching to position tasks, then divided into four subgroups and given the following bilateral lesions: (a) SHAM [vehicle injection into the nucleus basalis magnocellularis (NBM) and dorsal noradrenergic bundle (DNAB)], (b) DNAB (6-hydroxydopamine lesion of the DNAB, vehicle into the NBM), (c) NBM (quisqualic acid lesion of the NBM, vehicle into the DNAB) and (d) DUAL (neurotoxin lesions of both DNAB and NBM). Following postoperative recovery, the DUAL lesion subjects were slightly impaired, but by the seventh day of testing all groups were performing at similar levels. This strongly suggests that quisqualate lesions of the NBM are not sufficient to produce severe and lasting mnemonic disorders resembling those seen in Alzheimer's disease (AD). These data also indicate that the noradrenergic system may not be of critical importance with respect to cognition. It was reasoned that an additional anticholinergic treatment might exacerbate an underlying deficiency. All groups were injected, peripherally, with the cholinergic antagonist scopolamine (0-0.5 mg/kg). This drug dose-dependently disrupted performance in all groups. Moreover, the highest dose had a marked effect in the DUAL group, impairing performance even when no mnemonic burden was present (at zero delay). The results suggest that cholinergic NBM and noradrenergic DNAB lesions produce only transient mnemonic deficiencies. A combination of the two can be disruptive, but longer term task (or reference) memory is the primary process affected, and only under certain conditions. The implication of these findings to research concerning animal models relating to Alzheimer's disease is discussed.

Animals↗
PubMed1990

Postprandial changes in cytosolic free calcium and glucose uptake in adipocytes in obesity and non-insulin-dependent diabetes mellitus.

We evaluated the possible relationship between [Ca2+]i and glucose uptake in the postabsorptive state and postprandially in adipocytes obtained from normal and obese subjects, as well as from patients with non-insulin-dependent diabetes mellitus (NIDDM). Adipocytes isolated from overnight-fasted obese and NIDDM patients revealed high levels of [Ca2+]i (p less than 0.05 vs. control) in association with a decreased insulin-stimulated glucose uptake (p less than 0.05 vs. controls). In obese and NIDDM patients treated with oral hypoglycemic agents, the overnight fasting levels of [Ca2+]i were increased postprandially (p less than 0.05), concomitantly with a further decrease in insulin-stimulated 2-deoxyglucose uptake. Although the precise nature of the relationship between [Ca2+]i in specific insulin target tissues and diminished insulin action remains unknown, it is clear that high levels of [Ca2+]i may contribute to the development of insulin resistance.

Adipose Tissue↗
PubMed1989

Role of the spleen and rosette-formation response in experimental Eperythrozoon ovis infection.

The role of the spleen and rosette-formation responses was investigated in sheep experimentally infected with Eperythrozoon ovis. Phagocytic activity was observed in the spleen 19 days after primary infection. Phagocytosis of E. ovis-parasitised and non-parasitised erythrocytes by cordal reticular cells occurred. E. ovis organisms seemed to be detached from the erythrocytes by pseudopodia extending from macrophages and cordal reticular cells without causing damage to the plasmalemma of the erythrocyte. No phagocytic activity was observed in spleens removed 74 and 146 days after infection. Antigen-specific lymphoid cell responsiveness, assessed by rosette formation, indicated that 2.8, 15.4, 8.0 and 6.0% of lymphoid cells in the spleens of the four E. ovis-infected sheep, respectively, formed antigen-specific rosettes. Rosette formation did not occur when splenic lymphocytes from E. ovis-infected sheep were mixed with non-infected erythrocytes or when splenic lymphocytes from an uninfected sheep were used.

Anaplasmataceae Infections↗
PubMed1989

[D-TRP11]-neurotensin, unlike alpha-flupenthixol, may not block amphetamine-induced hyperactivity in rats.

Recent reports have suggested that neurotensin (NT) and some of its analogues resemble neuroleptics, for example alpha-flupenthixol (FLU), in their ability to suppress locomotor activity. The results obtained support this conclusion, but only if total photocell counts (the "traditional" index) are considered. An improved method of measuring activity--where subjects have to interrupt photocell beams in sequence before a ("conditional") count is registered--suggested, in direct contrast to the total counts index, that the stable analogue of neurotensin [D-Trp11]-neurotensin (DTNT) increased activity slightly (Sahgal and Keith, 1986). The present report is on the effects of DTNT (0-8 microgram/rat, i.c.v.) and FLU (0-1 mg/kg, i.p.) on hyperactivity induced by D-amphetamine (1.5 mg/kg, i.p.). The usual total counts index of activity suggested that FLU and DTNT blocked the increase. On the other hand, conditional count data suggested that only FLU was effective. Both measures indicated that FLU and amphetamine, administered separately, suppressed and enhanced activity, respectively. In contrast, DTNT at these doses had no significant effect on the conditional counts but markedly suppressed total counts. Subsequent observation of DTNT-treated rats placed in small open fields, suggested that the peptide induced marked circling (ambulatory) behaviour, at the cost of other behavioural categories, especially rearing and grooming. It is argued that (a) DTNT may not resemble neuroleptics in its effects on motor behaviour and (b) conditional activity counts, and also measures relating to brief interruptions of photocell beams, can provide useful additional information concerning motor activity.

Amphetamine↗