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Biomedical subjects

S Foster

Publications and source records attributed to S Foster.

At least 73 records · Page 4Linked to original sources
PubMed1992

Endothelin-1 actions on resorption, collagen and noncollagen protein synthesis, and phosphatidylinositol turnover in bone organ cultures.

The effects of endothelin-1 (ET) on several tissues are mediated by prostaglandins. In this study, we investigated the actions of ET on bone and determined whether they are mediated through prostaglandin-dependent pathways. Bone resorption, collagen, and non-collagen protein synthesis and inositol phosphate (IP) production were studied in neonatal mouse calvaria and fetal rat limb bone cultures. The effects of ET in the calvaria model were examined in the presence or absence of the cyclooxygenase inhibitor indomethacin (INDO). Bone resorption was stimulated by ET in the neonatal mouse calvaria, and this effect was inhibited by INDO. 45Ca release in the fetal rat limb bones was not affected by ET. ET stimulated collagen and noncollagen protein synthesis significantly in the calvaria model in the presence but not in the absence of INDO, suggesting that the anabolic effects of ET were masked by endogenous prostaglandin production. ET increased phosphatidylinositol turnover in both bone organ cultures. Although the addition of INDO reduced IP production slightly in the mouse calvaria, it was still significantly stimulated by ET. Our results demonstrate that ET has marked effects on bone tissue in vitro. Effects on resorption appear to be prostaglandin dependent, whereas the anabolic effects were not prostaglandin mediated. The stimulatory effects of ET on protein synthesis could be mediated through the IP signaling pathway. Since ET stimulates both bone resorption and anabolism, this peptide may have a role in the coupling of bone remodeling.

Animals↗
PubMed1992

Captopril and ANP: changes in renal hemodynamics, glomerular-ANP receptors and guanylate cyclase activity in rats with heart failure.

To define the renal effects of atrial natriuretic peptide (ANP) in heart failure, we studied rats with heart failure after coronary artery ligation. The rats received either captopril (2 milligrams drinking water) or placebo for 4 weeks. Glomerular filtration rate, renal plasma flow, filtration fraction, urine volume, urinary sodium excretion and the percent fractional excretion of sodium were measured before and after an infusion of ANP (0.3 microgram/kg/min). To determine whether changes in ANP receptor binding and responsiveness occur in heart failure and after captopril treatment, we performed radioreceptor binding studies and measured guanylate cyclase activity. Atrial natriuretic peptide in sham-operated rats decreased mean arterial pressure from 118 +/- 5 to 95 +/- 5 mm Hg (P less than .001), increased urine volume from 0.06 +/- 0.02 to 0.16 +/- 0.05 ml/min/kg (P less than .05), urinary sodium excretion, 14.2 +/- 3.1 to 41.4 +/- 8.9 mu eq/min/kg (P less than .02), filtration fraction from 0.30 +/- 0.03 to 0.40 +/- 0.4 (P less than .05), and the percent fractional excretion of sodium from 0.84 +/- 0.19 to 2.85 +/- 0.61 (P less than .02). Atrial natriuretic peptide in untreated rats with heart failure produced no significant systemic or renal hemodynamic effects. In rats with heart failure treated with captopril, ANP decreased mean arterial pressure from 93 +/- 4 to 86 +/- 4 mm Hg (P less than .05) and increased hematocrit from 50 +/- 2 to 52 +/- 1 (P less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Association of DQw7 (DQB1*0301) with ocular cicatricial pemphigoid.

Ocular cicatricial pemphigoid (OCP) is an autoimmune blistering disease that affects the conjunctiva and multiple mucous membranes. Class I and II and complement genetic markers of the major histocompatibility complex were studied in 20 Caucasian OCP patients and members of their families. Frequencies of individual alleles and common fixed or extended haplotypes in the patients were compared with those in normal family control haplotypes and with overall normal Caucasian haplotypes. The most striking increase compared with overall controls was noted in HLA-DQw3 (P = 0.006), unassociated with any extended haplotype. All but 1 of the 20 patients carried DQw3 in linkage with HLA-DR4 (increased significantly with P = 0.042 compared with overall normal genotype controls) or DR5. The DQw3, on analysis by restriction fragment length polymorphism in genomic DNA, was, in every instance, DQw7 (3.1, DQB1*0301). The frequency of DQB1*0301 in patient haplotypes compared with overall normal DR4 and DR5 DQw3-bearing haplotypes was statistically significantly increased (P less than 0.003, relative risk = 9.6). The distribution of homozygotes and heterozygotes for DQB1*0301 among the patients was consistent with dominant but not recessive inheritance of DQB1*0301 or a gene, probably a class II allele, in linkage disequilibrium with it as the major histocompatibility complex susceptibility gene for OCP.

Eye Diseases↗
PubMed1991

Supply and use of essential drugs in sub-Saharan Africa: some issues and possible solutions.

The paper describes drug supply systems in Africa, both public and private, and concludes that the 'private sector' may have serious drawbacks. Many opportunities exist for improving efficiency and reducing waste; the paper gives evidence for the savings to be made. Finally, there are several issues of specific importance to Africa, namely, geographic and spatial constraints to improving logistics, which are much more severe than elsewhere in the world; the problem of counterfeit drugs; financing of drug supplies and cost recovery; and the impact of the HIV/AIDS epidemic on supply and use of essential drugs.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Analysis of alkamides and caffeic acid derivatives from Echinacea simulata and E. paradoxa roots.

The constituents of the roots of Echinacea simulata and E. paradoxa were examined by HPLC. The major lipophilic and hydrophilic compounds could be identified. E. paradoxa contained several ketoalkenynes and proved to have almost identical constituents as E. pallida. E. simulata contained alkamides as found in E. angustifolia and in addition ketoalkenynes as in E. pallida. Echinacoside was found in both species.

Amides↗
PubMed1991

The combined effect of perioperative donor spleen cells or KCl-extracted antigen and cyclosporine on renal allograft survival in the rat.

The effects of using perioperative cyclosporine in conjunction with pretreatment with donor spleen cells or 3M KCl solubilized extracts of donor antigen were investigated in a LEW-to-DA rat renal allograft model. Cyclosporine given orally in a dose of 10 mg/kg/day around the time of transplantation (days -1, 0, +1), did not prolong renal allograft survival (median survival time [MST]--10 days). However when used in combination with pretreatment with either 10(8) donor spleen cells (1 day before transplantation), or 10(5) donor spleen cells (7 days before transplantation), pretreatment regimens that were in themselves ineffective, DA recipients accepted Lewis renal allografts indefinitely (MST greater than 100 days). Soluble antigen was prepared by 3M KCl extraction from donor spleen cells. Absorption assays were used to quantify the amount of class I major histocompatibility complex antigen in the preparation, and amounts of antigen equivalent to that expressed by 10(6)-10(8) donor spleen cells were used for pretreatment. These soluble antigen preparations given either 1 or 7 days before transplantation with or without perioperative cyclosporine did not prolong allograft survival of either homozygous or heterozygous donors (MST 10 days).

Animals↗
PubMed1991

Regionalized education and the accreditation process.

The concept of regionalized education is discussed in relation to its application to nurse anesthesia education. New approaches to the existing process of accreditation are proposed to facilitate this new system of delivery. The Council on Accreditation is seen as the body that should take a leadership role in bringing about change.

Accreditation↗
PubMed1990

Differential effects on cell killing in metallothionein overexpressing CHO mutant cell lines.

An increased level of metallothionein (MT) within the cytosol has been associated with the development of resistance to the cytotoxic effects of alkylating agents, but the mechanism of this effect is unclear. To verify the possible role of MT as a direct scavenger of alkylating agents we transfected two alkylating agent sensitive CHO mutant cell lines, methyl methanesulphate-1 and -2 (MMS-1 and MMS-2), with the human metallothionein II-A (hMTII-A) gene. From each mutant two transfected cell clones were isolated which were found to bear episomally 50 to 70 copies of the plasmid pMTII-BPV coding for the hMTII-A gene. The transfected cell lines contained between 1.4 and 4.9 micrograms of MT per 10(7) cells. This could be increased 2- to 9-fold by heavy metal induction. Transfectants derived from mutant MMS-1 were equally sensitive as the parental cells to a set of alkylating agents. However, transfectants derived from mutant cell line MMS-2 gained significant resistance to both N-methyl-N'-nitro-N-nitrosoguanidine and N-nitroso-N-methylurea, whilst retaining sensitivity to MMS. The degree of resistance was not increased by MT induction after heavy metal ion exposure. These results indicate that although resistance to alkylating agents may be mediated by a process which involves MT expression, this is not due to simple scavenging of the cytotoxic agent by the MT protein.

Animals↗
PubMed1990

Purification and characterization of a pi class glutathione S-transferase from human leukaemic cells.

The glutathione S-transferases are a group of enzymes involved in the detoxification of a wide range of xenobiotics. Elevation of the level of activity of glutathione S-transferases within the cytosol has been associated with the development of resistance to a number of cytotoxic drugs, including some commonly used in the treatment of leukaemia. In this paper we describe the purification and characterization of an anionic (p class) form of the enzyme from the peripheral blood of patients with acute myeloid leukemia, chronic myeloid leukaemia, and acute lymphocytic leukaemia and the spleen of a patient with chronic lymphocytic leukaemia. We present evidence that the form of enzyme purified closely resembles pi class glutathione S-transferase purified from human placenta. Immunoblotting performed on cytosol from the leukaemic cells from a range of cases of leukaemia at presentation, or on treatment, demonstrated that this form of glutathione S-transferase was the predominant isoenzyme expressed in all cases studied. However, in the limited number of cases studied there was no correlation between the level of expression and response to chemotherapy, suggesting that increased expression of pi class GST is not the sole cause of resistance to bifunctional alkylating agent in human leukaemias.

Aged↗
PubMed1990

Pulmonary rehabilitation in lung disease other than chronic obstructive pulmonary disease.

The benefit of pulmonary rehabilitation is well documented for patients with chronic obstructive pulmonary disease (COPD). However, such benefit has not been demonstrated for severely impaired patients with other chronic pulmonary diseases. Occasional non-COPD patients have been admitted to our 4-wk inpatient program. We compared the improvement of these non-COPD patients with that of COPD patients in the same program. Improvement is assessed by a 6-min walk test done at admission and discharge. On the admission 6-min walk test, 32 non-COPD patients had an ambulation distance of 276 +/- 219 ft (SD). At completion of the program, their ambulation distance increased to 574 +/- 367 ft (increase in ambulation 298 +/- 290 ft, P less than 0.0001). Diagnostic subgroups improved to essentially the same extent. The increase in ambulation was not statistically different between non-COPD patients and a series of 317 patients with COPD. Patients severely impaired with chronic pulmonary disease other than COPD benefit from intensive pulmonary rehabilitation, and the degree of improvement is similar to that of COPD patients.

Blood Gas Analysis↗
PubMed1990

Diaphragmatic paralysis without bulbar or limb paralysis in multiple sclerosis.

A patient is presented in whom disabling pulmonary symptoms in the absence of other significant disability complicated a long-standing course of MS. Clinical presentation and fluoroscopy confirmed the diagnosis of bilateral diaphragmatic paralysis. Magnetic resonance imaging revealed atrophy and extensive white matter changes within the cervical cord. This case is unique in that significant respiratory compromise due to cervical spinal cord involvement by MS was dissociated from bulbar dysfunction or profound limb paresis.

Adult↗
PubMed1989

The meaning of communication to a group of deaf college students: a multidimensional perspective.

The purpose of this study was to investigate the meaning of communication to deaf college students and to explore with them the range of skills and conditions that they consider important for communication. Ethnographic interviews with 23 first-year students at the National Technical Institute for the Deaf at Rochester Institute of Technology (NTID at RIT) were used to gather information about communication. Analysis of the interviews led to the organization of informants' comments into four dimensions of communication, including language-modality, affective, situational, and sociopolitical. These dimensions were then used to develop a multidimensional perspective on communication. The paper concludes with a discussion of the implications of a multidimensional perspective on communication for the development of comprehensive communication training programs for deaf people.

Communication↗
PubMed1989

Acute pulmonary edema associated with the use of oral ritodrine for premature labor.

We describe a patient who developed acute pulmonary edema while taking oral ritodrine for the treatment of premature labor and recovered after its discontinuation. The mechanism of development of pulmonary edema associated with beta-sympathomimetic agents is still not fully understood. Patients taking oral ritodrine should be observed for cardiopulmonary signs and symptoms.

Acute Disease↗
PubMed1988

Upper gastrointestinal Kaposi's sarcoma in patients positive for HIV antibody without cutaneous disease.

Six patients with antibodies to the human immunodeficiency virus (HIV) and with persistent gastrointestinal symptoms of HIV infection but without cutaneous lesions of Kaposi's sarcoma underwent endoscopy. Four also underwent barium meal examination. In all six cases small lesions were seen in the stomach at endoscopy, and histological examination of biopsy specimens taken from the lesions confirmed the diagnosis of Kaposi's sarcoma. The barium meal examinations were reported as normal in three patients and showed oesophageal candidiasis in the fourth. These findings suggest that Kaposi's sarcoma of the upper gastrointestinal tract is common in patients positive for HIV antibody, even those without cutaneous lesions. Endoscopy, with biopsy of suspicious lesions, is necessary to make the diagnosis and is recommended in all HIV antibody positive patients with persistent upper gastrointestinal symptoms.

Adult↗
PubMed1988

Delayed hypertension with electroconvulsive therapy.

A 74-year-old woman with essential hypertension underwent a course of electroconvulsive therapy (ECT) for the treatment of psychotic depression. Her treatments were associated with delayed and significant hypertension. Clonidine, which controlled her baseline blood pressure, was inadequate in treating her post-ECT hypertension. Acute treatment with hydralazine also failed. Labetalol, a short-acting beta-blocking agent with some alpha-1 blocking activity, worked well both acutely (intravenously) and orally to manage essential and ECT-induced hypertension.

Affective Disorders, Psychotic↗