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Biomedical subjects

R Hall

Publications and source records attributed to R Hall.

At least 109 records · Page 6Linked to original sources
PubMed1996

The clinical spectrum of postpartum thyroid disease.

The clinical and biochemical features of postpartum thyroid disease were analysed in 152 antithyroid peroxidase antibody-positive (anti-TPO+ve) women and compared with 239 anti-TPO-ve age-matched control postpartum women. All were assessed monthly for up to 12 months postpartum. Seventy three anti-TPO+ve women developed postpartum thyroiditis (PPT): 19.2% hyperthyroid alone, 49.3% hypothyroid alone, and 31.5% characterized by hyper- followed by hypothyroidism. None of the antibody-negative women developed any thyroid dysfunction. A significant increase in many of eleven symptoms of hypothyroidism and some of eight symptoms of hyperthyroidism compared to control women was observed in all anti-TPO+ve women, independent of thyroid status. This was particularly seen in women who later developed PPT when they were euthyroid, but was also observed in euthyroid anti-TPO+ve women who showed no decline of thyroid function during the postpartum period. Although PPT is usually transient, this condition, and the euthyroid antibody-positive state, may be associated with significant symptomatology, including an increased incidence of minor to moderate depression. Early recognition of this syndrome by antenatal screening of thyroid antibodies may contribute to improved management of women during the postpartum period.

Adult↗
PubMed1996

The comparative effects of sevoflurane versus propofol in the induction and maintenance of anesthesia in adult patients.

A randomized, prospective study was performed at four institutions to compare anesthetic induction, maintenance, and recovery characteristics between sevoflurane- and propofol-based anesthesia in 186 ASA physical status I and 11 patients undergoing elective surgical procedures of 1-3 h. Group 1 (n = 93) patients received sevoflurane-nitrous oxide for both induction and maintenance of anesthesia while Group 2 (n = 93) received propofol-nitrous oxide anesthesia. Induction of anesthesia and tracheal intubation times were significantly shorter with propofol (2.21 +/- 0.2 min, 5.11 +/- 0.3 min, respectively) than with sevoflurane (3.11 +/- 0.2 min, 7.21 +/- 0.3 min, respectively). Emergence times after sevoflurane (8.81 +/- 1.2 min) were significantly shorter than with propofol (13.21 +/- 1.2 min). Overall frequency of complication-free induction, maintenance, and emergence did not differ between the two anesthetic groups. However, side effects involving airway excitement were more prevalent during mask induction with sevoflurane as compared to propofol. Patients in the sevoflurane group were oriented and required postoperative analgesia much earlier than those who received propofol. Both groups were hemodynamically stable throughout the study period. The incidence of postoperative nausea, vomiting, and pain-discomfort scores were similar between the two groups. Urinary specific gravity decreased in the sevoflurane-treated group while serum creatinine and urinary pH were unchanged from preoperative values in both groups. Sevoflurane compared favorably with propofol when used for anesthesia for elective procedures of 1-3 h duration.

Adult↗
PubMed1996

Major histocompatibility complex class II and complement polymorphisms in postpartum thyroiditis.

The objective was to re-evaluate the association between class II HLA-DR and DQ MIIC antigens and postpartum thyroiditis (PPT) and to determine the prevalence of the class III complement allotypes of Properdin factor B (Bf), C4A and C4B in this condition. Two hundred and sixty-five (of 2897) pregnant women screened positive for thyroid autoantibody activity took part. Further blood samples were obtained for HLA class II (185) and complement (193) typing. The severity of the ensuing PPT was assessed by measuring thyroid function during the postpartum year. The HLA-DR and DQ phenotypes were assigned from restriction fragment length polymorphism analysis, and Bf, C4A and C4B allotypes were determined by immunofixation with anti-Bf or anti-C4 antibodies after electrophoresis. A weak association between the HLA class II antigens and PPT, as indicated by a reduced frequency of DR15 and DQ6 together with an increased frequency of-DR5 and DQ7, was confirmed. However, only the change in DR5 frequency remained significant after correction (corrected p < 0.05). Postpartum thyroiditis was also associated with frequency disturbances in BI and C4A allotypes but not C4B allotypes. Whilst this study has not provided evidence of a strong marker gene for PPT, it does not preclude the involvement of the MIIC in this condition. These data show disturbances in complement allotype frequencies, suggesting that the class III region may provide a useful focus for further study of this pathology.

Complement C4a↗
PubMed1996

Perioperative management of drug therapy, clinical considerations.

The objectives for the provision of a safe anaesthetic include rendering the patient analgesic for the procedure (amnesic if appropriate), with control of adverse haemodynamic perturbations, and muscle relaxation to facilitate surgery as necessary. This must be done with an understanding of the patient's pre-existing pathophysiology and drug therapy. This article focuses on the management of medications in the perioperative period from the practitioner's perspective. Areas of drug therapy examined include drugs affecting the cardiovascular, central nervous, haemostatic and endocrine systems. Review of the limited data available suggests that the safest course of action for the preoperative management of the vast majority of drug therapy is to continue such therapy until the time of surgery, particularly agents in which a withdrawal syndrome has been described, e.g. beta-adrenoceptor blocking agents, alpha 2-adrenoceptor agonists. Exceptions to this generalisation might include discontinuing ACE inhibitors prior to surgery as these agents may be associated with adverse haemodynamic changes during surgery. The management of drug therapy for patients receiving monoamine oxidase inhibitors (MAOIs) continues to be challenging due to the potential for drug interactions, e.g. severe hypertension with use of indirect-acting vasopressors and excitatory/depressive reactions with administration of pethidine (meperidine) or dextromethorphan. However, recent clinical experience has demonstrated the relative safety of continuing MAOIs prior to surgery by use of specific 'MAOI safe' anaesthetic techniques and/or substitution of short-acting MAOIs which do not irreversibly inhibit the enzyme. For drugs affecting the coagulation system, such as heparin and warfarin, prudence dictates discontinuing these agents whenever possible prior to surgery where it can be anticipated that haemorrhage will occur, e.g. vascular surgery, or where the consequences of even minor bleeding could be catastrophic, e.g. eye surgery. Controversy exists as to the management of patients receiving prophylactic low dose heparin for deep vein thrombosis prophylaxis or in whom intraoperative or postoperative anticoagulation is planned, e.g. aortic surgery, and in whom a regional anaesthetic technique is planned as part of the anaesthetic management. The data available suggest that, where prophylactic use of heparin is concerned, and provided the administration of the last dose of heparin and the institution of a regional anaesthetic nerve block does not occur at the same time, use of regional anaesthesia is not contraindicated in such circumstances. Where therapeutic anticoagulation is planned as part of the surgical management, there is a very small risk of the development of epidural or spinal haematoma when major central conduction nerve block is employed for anaesthesia, with resultant spinal cord compression and paralysis. These precautions do not apply to patients receiving aspirin or other nonsteroidal anti-inflammatory agents as there is a large clinical and published experience of the safety of regional anaesthesia in this group of patients. Patients treated with fibrinolytic agents are at increased risk for bleeding should surgery be required. For these patients, pre- and intraoperative use of agents with antifibrinolytic activity, e.g. aprotinin, has been demonstrated in case reports to be beneficial. Finally, recommendations for the management of patients who have received or are receiving glucocorticoids are given. Throughout the review, areas of uncertainty where further research is required are identified.

Animals↗
PubMed1996

Harmonization of animal clinical pathology testing in toxicity and safety studies. The Joint Scientific Committee for International Harmonization of Clinical Pathology Testing.

Ten scientific organizations formed a joint international committee to provide expert recommendations for clinical pathology testing of laboratory animal species used in regulated toxicity and safety studies. For repeated-dose studies in rodent species, clinical pathology testing is necessary at study termination. Interim study testing may not be necessary in long-duration studies provided that it has been done in short-duration studies using dose levels not substantially lower than those used in the long-duration studies. For repeated-dose studies in nonrodent species, clinical pathology testing is recommended at study termination and at least once at an earlier interval. For studies of 2 to 6 weeks in duration in nonrodent species, testing is also recommended within 7 days of initiation of dosing, unless it compromises the health of the animals. If a study contains recovery groups, clinical pathology testing at study termination is recommended. The core hematology tests recommended are total leukocyte (white blood cell) count, absolute differential leukocyte count, erythrocyte (red blood cell) count, evaluation of red blood cell morphology, platelet (thrombocyte) count, hemoglobin concentration, hematocrit (or packed cell volume), mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration. In the absence of automated reticulocyte counting capabilities, blood smears from each animal should be prepared for reticulocyte counts. Bone marrow cytology slides should be prepared from each animal at termination. Prothrombin time and activated partial thromboplastin time (or appropriate alternatives) and platelet count are the minimum recommended laboratory tests of hemostasis. The core clinical chemistry tests recommended are glucose, urea nitrogen, creatinine, total protein, albumin, calculated globulin, calcium, sodium, potassium, total cholesterol, and appropriate hepatocellular and hepatobiliary tests. For hepatocellular evaluation, measurement of a minimum of two scientifically appropriate blood tests is recommended, e.g., alanine aminotransferase, aspartate aminotransferase, sorbitol dehydrogenase, glutamate dehydrogenase, or total bile acids. For hepatobiliary evaluation, measurement of a minimum of two scientifically appropriate blood tests is recommended, e.g., alkaline phosphatase, gamma glutamyltransferase, 5' -nucleotidase, total bilirubin, or total bile acids. Urinalysis should be conducted at least once during a study. For routine urinalysis, an overnight collection (approximately 16 hr) is recommended. It is recommended that the core tests should include an assessment of urine appearance (color and turbidity), volume, specific gravity or osmolality, pH, and either the quantitative or semiquantitative determination of total protein and glucose. For carcinogenicity studies, only blood smears should be made from unscheduled sacrifices (decedents) and at study termination to aid in the identification and differentiation of hematopoietic neoplasia.

Animal Welfare↗
PubMed1995

The tribal tobacco policy project: working with Northwest Indian tribes on smoking policies.

BACKGROUND: This article reports on the objectives, study design, intervention methods, baseline results, and process data from a trial involving 39 Northwest Indian tribes. METHODS: Tribes were stratified and then randomized to either early or late intervention conditions. Intervention consisted of a consultation process to assist tribes to review and modify existing tobacco policies or to develop new policies relevant for their tribe and that protect tribal members from environmental tobacco smoke. Outcome measures consist of: (a) phone interviews to assess the comprehensiveness of tribal tobacco policy, (b) surveys of tribal leaders to assess norms and attitudes regarding tobacco use, and (c) observations of tribal settings to assess policy implementation and indicants of tobacco use. RESULTS: Early and later intervention tribes were well matched on baseline measures and tribal characteristics potentially related to policy outcomes. There was considerable variability across tribes on all measures though, in general, tribal leaders expressed support for more stringent tobacco use policies. Process data indicated that early intervention tribes strengthened their tobacco policies, but generally did not do so through tobacco policy committees as originally envisioned. CONCLUSIONS: There is good potential for tobacco policy interventions with Indian tribes. Consultation processes and products, such as policy guidebooks, that are sensitive to traditional uses of tobacco and to differences among tribes can help to modify policies to reduce exposure of tribal members to environmental tobacco smoke.

Attitude↗
PubMed1995

The influence of fluoride on the adsorption of proteoglycans and glycosaminoglycans to hydroxyapatite.

Proteoglycans and their spatial arms, the glycosaminoglycans, are known to interact with hydroxyapatite, and are considered to have a role in the regulation of mineralization. This study investigates the interactive mechanisms, with particular attention directed at the influence of fluoride on the adsorption process. Proteoglycans and glycosaminoglycans were adsorbed to hydroxyapatite in the presence of fluoride (1-20 ppm range). The adsorbates included a chondroitin 4-sulfate-rich proteoglycan extracted from rat incisor dentine, hyaluronan, chondroitin 4-sulfate, and dermatan sulfate. The order of glycosaminoglycan in decreasing affinity for hydroxyapatite was chondroitin 4-sulfate, dermatan sulfate, and hyaluronan, and the individual glycosaminoglycans showed different responses to the presence of fluoride. Graded increases in fluoride (1-4 ppm) led to 5-40% reduction of glycosaminoglycan adsorption to hydroxyapatite. The proteoglycan showed less affinity for hydroxyapatite, and demonstrated a reduction in adsorption of up to 22% with 20 ppm fluoride. The inhibitory effect of fluoride indicated an electrostatic mechanism, presumably via the calcium sites in the hydroxyapatite lattice.

Adsorption↗
PubMed1995

Who gets repeat screening mammography: the role of the physician.

To determine rates of, and explore physician factors associated with, repeat mammography, administrative data for 791 women aged 50 years and older were examined. Three-fourths of the women (73%) received repeat mammography (i.e., a second mammogram was obtained within six to 18 months of the first). Provider factors associated with higher repeat mammography rates were: being a woman, practicing in the women's health group rather than the general internal medicine service, and being a fellow or an attending physician (p-values < 0.01). Patients of women attendings/fellows had higher repeat mammography rates than did those of men attendings/fellows, men residents, and women residents. Characteristics (gender, level of training) of providers strongly influence their patients' screening behavior.

Boston↗
PubMed1995

Infection with Theileria annulata induces expression of matrix metalloproteinase 9 and transcription factor AP-1 in bovine leucocytes.

Theileria annulata infects bovine leucocytes and results in their reversible transformation such that they become immortalised and metastatic. The present study describes parasite-induced changes in host cell gene expression which have a direct bearing on this transformation process. T. annulata-infected leucocytes produce a number of novel metalloproteinase activities. One of these, previously called B1, is a 97-kDa protein which is secreted in large amounts and has been purified from protein-free, conditioned medium. An antiserum to this enzyme was used to isolate a cDNA clone. The predicted protein sequence of B1 is 81% identical to human matrix metalloproteinase 9 (MMP9), demonstrating that it is the bovine homologue of this enzyme. RNAase protection assays demonstrated that the MMP9 activity, unique to infected cells, is due to increased MMP9 mRNA levels. We also assayed the levels of transcription factor AP-1 and demonstrated that it was constitutively present in increased amounts in Theileria-infected cells. In addition we assayed the level of mRNA encoding c-Fos, a common component of AP-1 and observed that it was indeed up-regulated in infected cells. Since AP-1 is implicated in the control of the cell cycle, and MMP9 can confer metastatic properties, these results are of considerable significance with respect to the transformed phenotype induced by Theileria infection.

Amino Acid Sequence↗
PubMed1995

Transient expression of luciferase in Entamoeba histolytica driven by the ferredoxin gene 5' and 3' regions.

We have successfully transfected Entamoeba histolytica trophozoites with constructs containing ferredoxin sequences fused to the reporter gene luciferase. We have determined the conditions and parameters necessary to maximise transient luciferase expression in our system. Our optimal construct gave values of 268 x 10(3) relative light units per second (RLU s-1) when assayed representing a stimulation of 18,000-fold over the control vector. Comparison of differing constructs allowed us to conclude that the 5' and 3' ferredoxin sequences are both necessary for optimal luciferase expression from our vectors. Transcriptional initiation occurs within the consensus sequence ATTCA in both construct and chromosomal ferredoxin promoters.

Animals↗
PubMed1995

Theileria annulata sporozoite antigen fused to hepatitis B core antigen used in a vaccination trial.

A C terminal fragment (SR1) of SPAG-1, a sporozoite surface antigen of Theileria annulata, has been expressed as a fusion protein in the e1 loop of hepatitis B core antigen (HBcAg). This recombinant antigen (HBcAg-SR1) is produced in the form of self-assembling polyhedral particles which have been visualised under the electron microscope. Cattle immunised with HBcAg-SR1 produced high titres of neutralising antibodies. A significant T cell response to both the HBcAg and SR1 determinants was observed but evidence of a T suppressor determinant in SR1 was also revealed. Immunised cattle showed some evidence of protection to sporozoite challenge as assessed by severity of the disease. The significance of these findings for the development of a sub-unit vaccine against T. annulata is discussed.

Animals↗
PubMed1995

Arterial hypertension causing leg ulcers.

We report clinical and histological features of 16 consecutive patients with hypertensive leg ulcers. The lumen/wall ratio in arterioles at the edges of these hypertensive leg ulcers was compared with that in other types of chronic leg ulcers and was found to be significantly reduced (P < 0.001). Additional conditions such as venous hypertension or main vessel arterial disease contributed. Nineteen of 22 ulcers were completely healed after a mean of 4.9 months. Recognition of this condition enables correct treatment choice, which usually involves excision and grafting, and early healing.

Aged↗
PubMed1995

The status of bladder-preserving therapeutic strategies in the management of patients with muscle-invasive bladder cancer.

The recommended treatment for medically fit patients with muscle-invading bladder cancer is usually radical cystectomy. However, transurethral resection of the tumor, partial cystectomy, irradiation and systemic chemotherapy are each effective in some patients. These latter treatments allow bladder preservation and cure as an alternative to radical cystectomy although when used unselectively the survival rates are inferior to those of radical cystectomy. The updated results of conservative surgery, radiation therapy and systemic chemotherapy as monotherapy, as well as strategies of combined modality treatment were reviewed. Based on this review many areas of consensus were reached which include: 1. The primary goal of any treatment for a patient with muscle-invading bladder cancer is survival; bladder preservation in the interest of quality of life is a secondary objective. 2. Only a small proportion of carefully selected patients may be cured by transurethral surgery alone, or by partial cystectomy alone. 3. Radiation therapy is currently the standard bladder-preserving therapy against which all other bladder-preserving methods must be compared. 4. Systemic chemotherapy as monotherapy is inadequate and cannot be recommended. 5. The addition of cisplatin-containing systemic chemotherapy to radiation therapy or conservative surgery appears to improve local control. While no multi-modality therapeutic regimen has yet been shown to be clearly optimal with regard to local efficacy and minimizing toxicity, monotherapy for bladder preservation is probably not desirable as a routine approach. 6. Deferring the patient from immediate cystectomy does not appear to compromise survival, nor does the addition of primary systemic chemotherapy appear to significantly increase the morbidity of cystectomy or radiotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined Modality Therapy↗