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Biomedical subjects

L Shaw

Publications and source records attributed to L Shaw.

At least 109 records · Page 6Linked to original sources
PubMed1995

Short root anomaly in a patient with severe short-limbed dwarfism.

A 17-year-old youth was referred complaining of missing mandibular incisors and mobile canine teeth. He was extremely short (99 cm), with shortening of both trunk and limbs. A radiological skeletal survey showed abnormal and unusual findings, and his teeth were found to have short, conical roots and obliterated pulp chambers. Despite extensive biochemical and endocrinological investigation, it was concluded that the findings were not consistent with any recognized skeletal dysplasia nor with any recognized syndrome affecting the oral and dental tissues.

Adolescent↗
PubMed1995

In vitro techniques for erosive lesion formation and examination in dental enamel.

An in vitro experimental model has been developed for erosive lesion formation in dental enamel which can mimic in vivo conditions at the tooth surface. The features of this model provide a very reproducible method of producing erosive lesions in several teeth under identical conditions which can be varied to allow examination of a number of different parameters. A replica impression technique has also been developed for subsequent non-destructive microscopic examination of the lesions and comparison with in vivo lesions.

Acrylic Resins↗
PubMed1995

Ethanol, morphine and barbiturate alter the hemodynamic and cerebral response to cocaine in newborn pigs.

Newborns delivered to cocaine-abusing mothers are often exposed to other concurrently consumed illicit drugs, which may alter the hemodynamic and cerebral response to cocaine. This study examined the interaction of ethanol, morphine or barbiturate with cocaine on mean arterial pressure (MAP), cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) in newborn pigs. CBF, CMRO2 and cerebral O2 extraction (CEO2) were measured before and 4 and 10 min after cocaine (1.5 mg/kg i.v.) was administered in piglets that were awake, or pretreated with morphine, ethanol or pentobarbital. In awake piglets, cocaine increased CMRO2 and CEO2 while it had no significant effect on CBF. Conversely, in morphine- and ethanol-pretreated piglets, cocaine decreased CMRO2, decreased CBF and had not effect on CEO2. In awake piglets, cocaine increased MAP, whereas in morphine- or ethanol-pretreated piglets, cocaine decreased MAP. In the pentobarbital group, cocaine had no effect. These data demonstrate that other drugs of abuse alter the hemodynamic and cerebral effects of cocaine in the immature animal and may contribute to the central nervous system abnormalities in 'crack babies'.

Animals↗
PubMed1995

Plasma FSH, LH and immunoreactive inhibin concentrations in FecBB/FecBB and FecB+/FecB+ Booroola ewes and rams from birth to 12 months of age.

Endocrine and developmental changes were examined in Booroola FecBB/FecBB (BB, n = 16) and FecB+/FecB+ (++, n = 20) ewe lambs, and BB (n = 17) and ++ (n = 19) ram lambs from 2 to 53 weeks of age. Blood samples were taken weekly for the measurement of plasma concentrations of FSH, LH, immunoreactive inhibin, progesterone (ewe lambs) and testosterone (ram lambs). Behavioural oestrus in the ewe lambs and testicular volume and the breakdown of foreskin adhesions in ram lambs were recorded. Blood samples were taken from another flock of BB (n = 134) and ++ (n = 109) ram lambs at 20 weeks of age for the analysis of immunoreactive inhibin. In ewe and ram lambs, there appeared to be genotype differences for FSH, LH and immunoreactive inhibin at specific times during the neonatal period. In BB and ++ ewe lambs, respectively, mean FSH concentrations were 4.3 and 2.0 ng ml-1 (SED 0.54) between 4 and 6 weeks, 2.6 and 3.4 ng ml-1 (SED 0.33) between 12 and 28 weeks, and 1.8 and 1.9 ng ml-1 (SED 0.18) between 34 and 53 weeks of age. Mean plasma LH concentrations were lower in BB than in ++ ewe lambs from 26 to 53 weeks of age (P < 0.05) but not earlier. Mean concentrations of immunoreactive inhibin were also lower in BB than in ++ ewe lambs between 2 and 11 weeks (16.0 and 27.4 iu ml-1, respectively; P < 0.01), but thereafter no differences were apparent.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1995

Expression of gonadotrophin subunit genes in sheep that were homozygous carriers and non-carriers of the Booroola fecundity gene FecB.

Homozygous carriers (BB) of the Booroola fecundity gene FecB are characterized by high plasma concentrations of immunoreactive or biologically active FSH and, to a lesser extent, of immunoreactive LH, relative to non-carriers (++). Bovine cDNA probes for the alpha gonadotrophin, FSH beta and LH beta genes were used to investigate FecB-specific differences in the mRNA species for the gonadotrophin subunits in pituitaries obtained from ++ and BB mid-luteal phase ovary-intact ewes, ovariectomized ewes and ovary-intact or ovariectomized ewes with hypothalamic-pituitary disconnection (HPD) given the same regimen of pulsatile GnRH. No FecB-specific differences in the number or size of mRNA transcripts detected by northern blotting were noted for any of these genes. Densitometry of the northern blots revealed no significant FecB-specific differences in the relative amounts of mRNA encoding alpha gonadotrophin, FSH beta or LH beta in the pituitaries from any of the experimental groups of ++ and BB sheep. Furthermore, there were no significant FecB-specific differences in the pituitary content of FSH or LH in these animals, despite significantly higher plasma concentrations of FSH in the ovary-intact and ovariectomized HPD groups. These data show that whereas the FecB gene causes increased plasma concentrations of FSH, no consistent effects can be demonstrated on pituitary gonadotrophin content or on gonadotrophin subunit gene transcription, using northern analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Amifostine (WR-2721) shortens the engraftment period of 4-hydroperoxycyclophosphamide-purged bone marrow in breast cancer patients receiving high-dose chemotherapy with autologous bone marrow support.

4-Hydroperoxycyclophosphamide (4-HC), a commonly used marrow-purging agent, is active against many tumors, but is also toxic to normal marrow progenitors. Amifostine (WR-2721) is a sulfhydryl compound with chemoprotectant activity. Preclinical studies using suspensions of bone marrow and breast cancer cells demonstrated that ex vivo treatment with amifostine followed by 4-HC resulted in protection of marrow progenitors, with no compromise in the antitumor effect of 4-HC. This fact stimulated the development of a clinical trial. Bone marrow was harvested from 15 poor-prognosis breast cancer patients and randomly assigned to ex vivo treatment with amifostine followed by 4-HC (amifostine + 4-HC), or treatment with 4-HC alone. High-dose chemotherapy was then administered followed by infusion of the purged autologous bone marrow support (ABMS). Leukocyte engraftment, defined as a white blood cell count > or = 1 x 10(9)/L, was achieved in an average of 26 days for patients whose marrow was purged with amifostine + 4-HC versus 36 days for patients whose marrow was purged with 4-HC alone (P = .032). The average number of platelet transfusions (12 v 29; P = .017) and days of antibiotic therapy (28 v 40; P = .012) were significantly less for patients whose marrow was exposed to amifostine + 4-HC, compared with 4-HC alone. Unpurged backup marrow fractions were infused into three patients whose marrow was purged with 4-HC alone, because of inadequate marrow recovery. None of the patients who received amifostine + 4-HC-purged marrow required a backup marrow fraction. Complete remissions were achieved in 83% of patients with measurable disease, with no difference between the two cohorts. Forty-three percent of patients remained alive and progression-free at a mean of 13 months posttransplant. There was no significant difference in the rate or pattern of relapse for patients whose marrow was purged with amifostine + 4-HC compared with those whose marrow was purged with 4-HC alone. Ex vivo treatment of marrow with amifostine significantly shortens the time to marrow recovery, thereby reducing the risk of myelosuppressive complications in breast cancer patients receiving high-dose chemotherapy and 4-HC-purged ABMS. Since supportive care requirements are also significantly decreased, amifostine may reduce the cost of such therapy.

Adult↗
PubMed1994

Ethnic differences in diabetes knowledge and education: the South Auckland Diabetes Survey.

AIM: To compare the knowledge of diabetes, and diabetes education provision/preferences among European, Maori and Pacific Islands diabetic patients in south Auckland. METHOD: The 331 European, 86 Maori and 123 Pacific Islands patients who were interviewed attended local diabetes services and a stratified subsample of general practitioners. Interviews included closed and open questions of diabetes knowledge, age, sex, diabetes treatment, employment status, weekly household income, school/further education received and the actual and preferred format of diabetes education. RESULTS: Pacific Islands patients knew least, and Europeans most, about diabetes from both open and closed diabetes knowledge questions. The majority of Pacific Islands patients could not name the nature, symptoms or complications of diabetes. This was unaffected by duration of diabetes, place of birth or time in New Zealand, although insulin treated Pacific Islands patients knew more than noninsulin treated patients (closed score 71 SD (4)% vs 61 SD (2)% p < 0.05). Pacific Islands patients were least likely to have received diabetes education (European 69%, Maori 70%, Pacific Islands 49%, p < 0.001). Knowledge scores were higher in those who had received education at diagnosis. Europeans were least likely to want further education (Europeans 52%, Maori 69%, Pacific Islands 63%, p < 0.01). The preferred sources for ongoing education were the lay educator/diabetes nurse specialist service (Europeans 28%, Maori 37%, Pacific Islands 76%), and the hospital based clinic among Europeans (27%) and Maori (36%). No Pacific Islands patients preferred a hospital based ongoing education service, while few diabetic patients of any ethnic group preferred to receive education via their general practitioner. In all ethnic groups, patients wanting more education knew more than those who did not. CONCLUSION: The local delivery of diabetes education is uneven. Among Pacific Islands people, it is grossly inadequate. In order for all patients to receive such education, the diabetes services need to be better coordinated and integrated with primary health care.

Aged↗
PubMed1994

CMP-N-acetylneuraminic acid hydroxylase from mouse liver and pig submandibular glands. Interaction with membrane-bound and soluble cytochrome b5-dependent electron transport chains.

In this report, the nature of the protein components involved in the functioning of cytidine-5'-monophosphate-N-acetylneuraminic acid (CMP-Neu5 Ac) hydroxylase in high-speed supernatants of mouse liver has been investigated. Fractionation and reconstitution experiments showed that this enzyme system consists of NADH-cytochrome b5 reductase, cytochrome b5 and a 56-kDa terminal electron acceptor having the CMP-Neu5 Ac hydroxylase activity. This enzyme system is extracted in a soluble protein fraction; however, the amphipathic, usually membrane-associated, forms of cytochrome b5 and the reductase were found to predominate and are presumably the forms which support the turnover of the hydroxylase in vivo. Although the majority of cellular cytochrome b5 and cytochrome b5 reductase is membrane-bound, the addition of intact microsomes elicited no significant increase in the hydroxylase activity of supernatants. Detergent-solubilised microsomes, however, potently activated the hydroxylase, probably due to the greater accessibility of the cytochrome b5. Accordingly, in reconstitution experiments, pure hydrophilic cytochrome b5 interacts more effectively with the hydroxylase than isolated amphipathic cytochrome b5. Studies on the CMP-Neu5 Ac hydroxylase system in fractionated porcine submandibular glands and bovine liver suggest that the composition of this enzyme system is conserved in all mammals possessing sialoglycoconjugates containing N-glycolylneuraminic acid.

Animals↗
PubMed1994

Purification, characterization and reconstitution of CMP-N-acetylneuraminate hydroxylase from mouse liver.

CMP-N-acetylneuraminate hydroxylase was isolated from mouse liver high speed supernatant with a yield of 0.4% and an apparent 1000-fold purification. The enzyme is a monomeric protein with a molecular weight of 66 kDa, as determined by gel filtration and SDS-PAGE. The hydroxylase system was reconstituted with Triton X-100-solubilized mouse liver microsomes and purified soluble or microsomal forms of cytochrome b5 reductase and cytochrome b5. The systems were characterized in detail and kinetic parameters for each system were determined.

Animals↗
PubMed1994

Out-patient medical care in Edinburgh for IDU-related HIV.

Using combined medical and drug clinics, by the end of 1990 we had initiated contact with 511 HIV positive individuals, 75% injection drug use (IDU) related. We have previously reported a significant reduction in the number of missed appointments from 1985-89 following the introduction of methadone and an all day clinic, but between 1989 and 1990 the appointment default rate rose from 17 to 25%. A significant percentage increase in missed appointments was, however, only seen in those not attending the all day clinic (chi 2(3) = 121.3, p < 0.001). An analysis of the patients missing appointments during 1989-90 revealed that 36-45% of patients attending each year missed only 1 or 2 appointments, that the majority of missed appointments each year were accounted for by less than 20% of the patients, around 60% of these patients missed appointments in both years and that only 2% of patients attending both years consistently miss 3 or more appointments per year. Laboratory monitoring of HIV, that is at least one sampling episode in a year, was achieved, however, in 92-95% of the patients attending each year. The annual number of patients lost to follow-up varied between 7 and 11% per year, but did not change significantly over time, whilst the cumulative number of HIV infected individuals lost to follow-up after 5 years was only 14%. Between 1986 and 1990 self-reported reduction in IDU was more likely in HIV positive than negative individuals; the number of HIV positive individuals who reported injecting for more than 50% of the year fell from 40 to 5% (chi 2(4) = 15.23, p < 0.01) whilst the number who reported at least one injection per year fell from 51 to 23% (chi 2(4) = 62.06, p < 0.001). By comparison amongst non-HIV-infected patients the percentage who reported opiate use for more than 50% of the visits during a year rose from 54% in 1986 to a peak of 70% in 1989 (chi 2(4) = 10.22, p < 0.05) and those who reported opiate use at least once during the year rose from 57% in 1986 to a peak of 75% in 1989 (chi 2(4) = 14.3, p = 0.006). Combined medical and drug clinics from 1986 to 1990 together with a multi-disciplinary team approach to medical care was successful in delivering health care to HIV-infected injection drug users.(ABSTRACT TRUNCATED AT 400 WORDS)

Ambulatory Care↗
PubMed1994

Purification and characterization of CMP-N-acetylneuraminic acid hydroxylase from pig submandibular glands.

N-Glycoloylneuraminic acid (Neu5Gc) is synthesized as its CMP-glycoside by the action of CMP-N-acetylneuraminic acid (CMP-Neu5Ac) hydroxylase. This enzyme is a soluble cytochrome b5-dependent monooxygenase and has been purified to apparent homogeneity from pig submandibular glands by precipitation with N-cetyl-N,N,N-trimethylammonium bromide and fractionation on Q-Sepharose, Cibacron Blue 3GA-Agarose, Reactive Brown 10-Agarose, Hexyl-Agarose and Superose S.12. This procedure resulted in an 8960-fold purification of the hydroxylase with a recovery of 0.8%. The molecular mass of this protein was shown to be 65 kDa on SDS-PAGE and approximately 60 kDa as determined by gel filtration on Superose S.12, which suggests that the enzyme is a monomer. The purified CMP-Neu5Ac hydroxylase is activated by FeSO4 and inhibited by iron-binding reagents such as o-phenanthroline, KCN, Tiron and ferrozine. An apparent Km of 11 microM was determined for the substrate CMP-Neu5Ac using purified hydroxylase in the presence of Triton X-100-solubilized microsomes. In a reconstituted system consisting of purified hydroxylase, cytochrome b5, cytochrome b5 reductase and catalase, an apparent Km of 3 microM was measured. The apparent Km for cytochrome b5 in this system was 0.24 microM. Immunization of a rabbit with enriched and purified hydroxylase led to an antiserum that inhibited CMP-Neu5Ac hydroxylase activity and reacted with the purified 65 kDa protein on a Western blot after SDS-PAGE. Antibodies specific for this 65 kDa protein were isolated and showed a strong reaction with the purified CMP-Neu5Ac hydroxylase from mouse liver after immunoblotting.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

The distribution and severity of tooth wear and the relationship between erosion and dietary constituents in a group of children.

There is very little published information on the severity of tooth wear in children. The current investigation involved clinical examination of 101 children and an assessment of their dietary habits. Evidence of tooth wear was found in over 80% of maxillary incisor teeth, and 30% of primary molar teeth had some dentine exposed. There were 21 children who were regarded as having 'mild' erosion, 45 'moderate' erosion and 35 'severe' erosion. There were highly statistically significant differences between the three groups in relation to drinking habits; the mean number of carbonated drinks consumed per week by children in the 'mild', 'moderate' and 'severe' erosion groups was 3.9, 5.8 and 13.9 respectively, of fruit drinks 10.3, 16.4 and 18.3, and of all fruit-based drinks 17.9, 27.1 and 39.0. There were also highly significant differences in those having a fruit-based drink at bed-time; 14% in the 'mild' erosion group, 32% in the 'moderate' and 60% in the 'severe' group. Although fresh fruit and yoghurt consumption followed the same trend, this did not reveal statistically significant differences. It is important to identify children who exhibit clinical evidence of erosion so that advice can be given about consumption of acidic dietary constituents.

Adolescent↗
PubMed1994

Plasma concentrations of FSH, LH, thyroid-stimulating hormone and growth hormone after exogenous stimulation with GnRH, TRH and GHRH in Booroola ewes that are homozygous carriers or non-carriers of the FecB gene.

The aim of the present study in Booroola ewes, either homozygous (BB) or non-carriers (++) of the FecB gene, was to test the specificity of the pituitary responses to exogenous hypothalamic releasing hormones by examining the plasma concentrations of FSH, LH, thyroid-stimulating hormone (TSH) and growth hormone (GH) after injecting the animals with different doses of GnRH, thyroid-releasing hormone (TRH) or growth-hormone-releasing hormone, (GHRH) which were administered on separate occasions. The animals (n = 8 per dose) received 0, 3.1 or 12.5 micrograms of thyroid-releasing hormone and GnRH (i.v.), whereas they (n = 9-13 per dose) received 0, 6.0 or 16.0 micrograms GHRH (i.v.). For each experiment there were no differences between the genotypes in bodymass or age. Gene-specific differences in the mean pretreatment concentrations of plasma FSH (BB > ++; P < 0.05) but not of LH, TSH or GH were noted. After treatment with GnRH, TRH or GHRH, significant effects of dose were noted for all the hormones; however, a gene-specific effect was observed only for FSH in response to GnRH (BB > ++; P < 0.01) with no genotype x dose interaction (ANOVA). For LH, the effects of genotype and the genotype x dose interaction almost reached significance at the 5% level (genotype, P = 0.055; genotype x dose, P = 0.067). For TSH and GH the respective genotype x dose interactions were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Erosion in children: an increasing clinical problem?

Tooth wear is becoming more common in both adults and children. The triad of attrition, abrasion and erosion has been known for many years, but the contribution of erosion (irreversible loss of dental hard tissue due to a chemical process not involving bacteria, or the loss of tooth surface not directly associated with mechanical or traumatic factors or caries) to excessive loss of tooth tissue is now being emphasized. The authors of this paper examine the problem and suggest ways of overcoming it.

Beverages↗
PubMed1993

Comparison of the Asymptomatic Cardiac Ischemia Pilot and modified Asymptomatic Cardiac Ischemia Pilot versus Bruce and Cornell exercise protocols.

The Asymptomatic Cardiac Ischemia Pilot (ACIP) and modified ACIP treadmill exercise protocols were developed to test patients with coronary artery disease and to linearly increase work load between stages. The physiologic changes that occurred with ACIP and modified ACIP were compared to those with the Bruce and Cornell protocols in 28 normal subjects and 16 men with coronary artery disease. The exercise protocols were randomly assigned over 2 days, and gas exchange data were obtained continuously with each test. In normal subjects, the peak heart rate, systolic blood pressure, peak oxygen consumption rate (VO2) and minute ventilation were similar for the 4 protocols tested, with exercise time shortest for the Bruce protocol in comparison with the ACIP, modified ACIP and Cornell protocols (10.2 +/- 3.1 vs 13.4 +/- 4.9, 13.9 +/- 4.5, and 15.0 +/- 4.2 minutes, respectively; p < 0.001). The difference between predicted and observed VO2 was smallest for the ACIP protocol (37.0 +/- 11.0 vs 35.8 +/- 13.5 ml/kg/min) and greatest for the Bruce protocol (41.1 +/- 11.8 vs 36.7 +/- 15.0 ml/kg/min) in normal subjects, as well as in patients with coronary artery disease (ACIP protocol 26.9 +/- 7.1 vs 22.5 +/- 6.7, and Bruce protocol 29.1 +/- 7 vs 22.6 +/- 5.7 ml/kg/min, respectively). The ratio of VO2 to work rate, expressed as a slope, was similar in normal subjects for the 4 protocols tested. However, in patients with coronary artery disease, the slope was 0.84 and 0.83 for the ACIP and modified ACIP protocols, respectively, versus 0.61 and 0.71 for the Bruce and Cornell protocols, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Catalytic properties of the CMP-N-acetylneuraminic acid hydroxylase from the starfish Asterias rubens: comparison with the mammalian enzyme.

The biosynthesis of N-glycolylneuraminic acid (Neu5Gc) was investigated in cell-free extracts of the starfish Asterias rubens, which is one of the evolutionarily least-advanced species known to possess Neu5Gc-containing glycoconjugates. As in higher animals, Neu5Gc is synthesised in Asterias rubens by the action of a CMP-Neu5Ac hydroxylase. Enzyme activity was detected in all starfish tissues tested, the turnover being the greatest in the gonads. The enzyme from this tissue has a temperature optimum between 25 and 33 degrees C and a pH optimum between pH 6.0 and 6.4. This hydroxylase exhibits many characteristics in common with the mammalian enzyme. For example, the enzyme is extracted in a predominantly soluble form. Oxygen and a reduced pyridine nucleotide are necessary for activity, with NADH being the most effective cofactor. Furthermore, the activation of the hydroxylase by exogenously added iron salts and the potent inhibitory effects of several iron ligands point to the involvement of a non-haem iron cofactor. The enzyme has a high affinity for the substrate CMP-Neu5Ac, the apparent Km being 18 microM. In contrast to the mammalian enzyme, the hydroxylase from Asterias rubens is not inhibited by increased ionic strength and cannot be activated by non-ionic detergents. Moreover, the CMP-Neu5Ac turnover increased linearily with increasing protein concentration. In accordance with other enzymes in starfish, seasonal changes in the CMP-Neu5Ac hydroxylase activity were also observed.

Animals↗
PubMed1993

Value of the history and physical in identifying patients at increased risk for coronary artery disease.

OBJECTIVE: To determine whether information from the physician's initial evaluation of patients with suspected coronary artery disease predicts coronary anatomy at catheterization and 3-year survival. DESIGN: Prospective validation of regression model estimates in an outpatient cohort. SETTING: University medical center. PATIENTS: A total of 1030 consecutive outpatients referred for noninvasive testing for suspected coronary artery disease; 168 of these patients subsequently underwent catheterization within 90 days. MEASUREMENTS: Information from the initial history, physical examination, electrocardiogram, and chest radiograph was used to predict coronary anatomy (the likelihood of any significant coronary disease, severe disease [left main or three-vessel], and significant left main disease) among 168 catheterized patients and to estimate 3-year survival among all patients. These estimates were compared with those based on treadmill testing. Cardiovascular testing charges were calculated for all patients. RESULTS: Predicted coronary anatomy and survival closely corresponded to actual findings. Compared with the treadmill exercise test, initial evaluation was slightly better able to distinguish patients with or without any coronary disease and was similar in the ability to identify patients at increased risk for dying or with anatomically severe disease. Based on arbitrary definitions, 37% to 66% of patients were at low risk and responsible for 31% to 56% of the charges for cardiovascular testing. CONCLUSIONS: The physician's initial evaluation, despite the subjective nature of much of the information gathered, can be used to identify patients likely to benefit from further testing. The development of strategies for cost-conscious quality care must begin with the history, physical examination, and simple laboratory testing.

Aged↗