Adverse reactions to St John's Wort

OBJECTIVE

To report 2 cases of adverse reactions to St John's wort, a popular herbal treatment for depression.

METHOD

We present 2 case histories and review the existing literature regarding St John's wort.

RESULTS

St John's wort may cause serotonin syndrome in sensitive patients. In addition, St John's wort may be associated with hair loss.

CONCLUSIONS

For clinical reasons, it is important to recognize and report adverse reactions to herbal remedies and to document that these treatments have side effects commensurate with their potent action on brain neurochemistry.

Coping and psychosocial adjustment of women with diabetes

PURPOSE

The purpose of this study was to investigate relationships between coping styles and psychosocial adjustment for women with diabetes.

METHODS

The sample consisted of 115 community-residing women with diabetes. Coping was measured by the Revised Jalowiec Coping Scale and psychosocial adjustment by the Psychosocial Adjustment to Illness Scale. Pearson's product moment correlation was used to assess relationships between coping and adjustment.

RESULTS

The most frequently and effectively used coping styles were optimistic, confrontive, self-reliant, and supportant. The psychological, social, and health care domains showed the most problems; the fewest were in the extended family, sexual, and vocational domains. Relationships were found between women's coping styles and psychosocial adjustment, with better adjustment associated with effective use of confrontive, supportant, optimistic, self-reliant, and palliative coping styles.

CONCLUSIONS

Important relationships exist between the ways women cope with diabetes and their level of psychosocial adjustment to the illness. Knowledge of these relationships can help diabetes educators assist clients in making lifestyle changes.

The effect of a high-fat meal on the oral bioavailability of the immunosuppressant sirolimus (rapamycin)

The bioavailability of an oral nonaqueous solution of sirolimus was compared under fasting conditions and after a high-fat meal in a randomized, two-way crossover pharmacokinetic study. Healthy volunteers were administered a 15 mg single dose of sirolimus on two occasions, once while fasting and once after consumption of a high-fat breakfast. Whole blood concentrations of sirolimus were assayed by using a validated method with high-performance liquid chromatography/tandem mass spectrometric detection. Sirolimus was absorbed more slowly when administered after a high-fat meal than when administered after fasting, as shown by statistically significant reductions in peak concentration (Cmax) and the ratio of Cmax to the area under the curve (AUC), and lengthening of the time to peak concentration. The oral availability of sirolimus was increased to a modest extent (35%) and in a uniform manner when administered with a high-fat meal; the geometric mean ratio of the fed/fasting AUC values was 1.35, with a 90% confidence interval of 1.26 to 1.46. Food had no effect on the terminal half-life of sirolimus (mean values of 67 to 68 hours). The 35% increase in AUC obtained after a high-fat meal appears small relative to the intersubject and intrasubject variabilities observed in clinical trials. However, to minimize unnecessary fluctuations in trough whole blood sirolimus concentrations, it is advisable that sirolimus be administered consistently in individual patients, either with or without meals.

Spiritual well-being among older adults

1. Older adults are a highly spiritual and religious group of individuals. 2. Nurses neglect spiritual interventions for older adults because of a fear of imposing their own philosophies, and lack of knowledge about the abstract. 3. Nurses need to be aware of spiritual needs not related to Judeo-Christian concepts. 4. The profound benefits to humankind of religious practice and spiritual well-being among most life forms has been reported.

The relation of ethnic identification with cigarette smoking among US urban African American and Latino youth: a pilot study

Primarily African American and Latino seventh graders (N = 545) attending health and science classes at three urban Southern California junior high schools were administered a 13-item ethnic identification assessment during one class period, to investigate the relationship between ethnic identification and tobacco use. For African Americans, the perception of looking different from other ethnic groups was found to be associated with avoidance of peer tobacco use. Among Latinos, the perception of being liked by other ethnic groups, and enjoying interaction with people outside of their ethnic group, were found to be associated with negating peer influence for tobacco use. Watching television shows with main characters of same ethnic group was associated with being able to make friends without using tobacco, for both ethnic groups. For Latinos, ever trying a cigarette was associated with the perception of being liked by other ethnic groups. These results suggest there may be elements inherent in ethnic identification protective against peer influence for smoking among ethnic minority youth. Also, acculturation of Latinos to the majority population may increase their risk for experimentation with tobacco products.

Pharmacokinetics of the aldose reductase inhibitor tolrestat: studies in healthy young and elderly male and female subjects and in subjects with diabetes

Tolrestat is an aldose reductase inhibitor undergoing clinical trials in diabetic subjects that may reduce the severity of chronic tissue damage associated with hyperglycemia. These studies were conducted to evaluate the pharmacokinetics of tolrestat in healthy young and elderly male and female subjects and in young and elderly subjects with diabetes. The drug was administered in a multiple-dose regimen, and steady-state parameters were obtained. There were no important gender-related differences, but mean values for apparent oral clearance, renal clearance, and corresponding unbound parameters were significantly lower for the elderly healthy subjects than for the young healthy subjects. The drug is highly bound to plasma proteins, and the unbound fraction (0.75%) did not differ among the subjects. The results from young and elderly diabetic subjects suggest that diabetes per se has no influence on tolrestat disposition but that there is an age-related reduction in apparent oral clearance (30 versus 18 ml/hr/kg) and a corresponding increase in the minimum steady-state plasma concentration (1.2 versus 1.9 micrograms/ml). These data indicate a possible need to reduce the dose of tolrestat in elderly subjects, assuming the same concentration-response relationship.

Dimerization of the extracellular domain of granuloycte-colony stimulating factor receptor by ligand binding: a monovalent ligand induces 2:2 complexes

Granulocyte-colony stimulating factor (G-CSF) binds to a specific cell surface receptor and induces signals for growth and differentiation in cells of granulocyte hematopoietic lineage. In order to understand how G-CSF binding initiates signals into these cells, we have studied its interactions with the entire extracellular domain of the receptor (sG-CSFR). The sG-CSFR was purified from CHO cell conditioned media with a G-CSF affinity column, resting in a preparation fully competent for ligand binding. However, when sG-CSFR was purified by conventional means, i.e., without affinity chromatography, only about half was competent. Therefore, all studies were carried out using affinity-purified material. The sG-CSFR exhibited a weak self-association into a dimer with a dissociation constant of 200microM in the absence of G-CSF. Addition of G-CSF dimerizes the receptor, with a preferred stoichiometry of 2 G-CSF molecules plus 2 receptors. Unexpectedly, receptor-receptor interactions rather than through two receptors binding to the same G-CSF molecule; i.e., G-CSF is a monovalent ligand. G-CSF binding to the receptor monomer occurs with high affinity. The binding of G-CSF also enhances the receptor-receptor dimerization; when G-CSF is bound to both receptors, dimerization is enhanced 2000-fold, while the interaction of a 1:1 receptor-ligand complex with a second ligand-free receptor is enhanced 80-fold. Thus, the mechanism of receptor dimerization is fundamentally different than that of related cytokine receptors such as growth hormone and erythropoietin receptors. Circular dichroic spectra showed a small but significant conformational change of receptor upon binding G-CSF. This is consistent with the idea that G-CSF binding alters the conformation of the receptor, resulting in an increase in receptor-receptor interactions.

Identification and characterization of a soluble c-kit receptor produced by human hematopoietic cell lines

Stem cell factor (SCF) triggers cell growth by binding to cell surface c-kit receptors. Soluble forms of several cytokine receptors have been described and may play a role in the modulation of cytokine activity in vivo. For these reasons, we investigated whether human hematopoietic cells produce soluble c-kit receptors. The human leukemia cell lines OCIM1 and MO7e display approximately 80,000 and approximately 35,000 high-affinity cell surface c-kit receptors, respectively. Soluble c-kit receptors were detected by enzyme immunoassay in OCIM1 and MO7e culture supernatants. We determined the molecular weight and binding affinity of soluble c-kit receptor produced by OCIM1 cells, soluble c-kit receptor purified from human serum, and recombinant soluble c-kit receptor expressed in CHO cells. The three soluble c-kit receptors each have a molecular weight of 98 kD. Quantitative binding experiments with 125I-SCF indicate that the soluble c-kit receptors obtained from human serum or OCIM1 cells have binding affinities for SCF of approximately 200 to 300 pmol/L, in contrast to the recombinant form, which has a binding affinity of approximately 1.5 nmol/L. All three forms of the soluble c-kit receptor were able to compete with c-kit receptors on OCIM1 cells for 125I-SCF binding. Thus human hematopoietic cells can produce a soluble form of the c-kit receptor that retains high-affinity SCF binding activity. We speculate that the soluble c-kit receptor may bind SCF and function as a receptor antagonist in vivo.

Structural requirements for addition of O-linked carbohydrate to recombinant erythropoietin

To define the structural requirements for addition of O-linked glycosylation in vivo, recombinant erythropoietin (rEPO) variants were constructed. Thirty-three independent Ser or Thr substitutions were constructed and examined to see which were subject to O-linked carbohydrate addition. Variants with Thr mutations at positions 123 and 125, but not elsewhere, contained additional carbohydrate, which suggests that several positions around the existing O-linked glycosylation site (Ser126), but not elsewhere, contain the necessary information for O-linked carbohydrate addition. Two forms of the Thr125 variant were identified. One form was glycosylated only at residue 125, and a second form was glycosylated at both Thr125 and Ser126, the normal O-glycosylation site. We have also found that glycosylation is less efficient when rEPO is improperly folded and that prolines at -1 and +1 relative to the O-glycosylation site enhance glycosylation.

Social isolation does not alter brain regional benzodiazepine binding site numbers, affinity and coupling in the rat

Male Sprague-Dawley rats were differentially housed for 21 days immediately after weaning. Isolated animals showed a selective suppression of exploration of the light side of a two compartment box; spending significantly less time in the light, and making fewer transitions between the light and dark compartments compared to socially reared controls. However, both basal and GABA-stimulated [3H] flunitrazepam binding was unaltered in the frontal cortex, hippocampus, amygdala and cerebellum following social isolation. These results are discussed in relation to other studies on central benzodiazepine receptor changes following a variety of experimental stressors.

Deficits in exploratory behaviour in socially isolated rats are not accompanied by changes in cerebral cortical adrenoceptor binding

Social isolation of rats produces marked deficits in exploratory behaviour in a novel environment. To test our hypothesis that adrenoceptors are modified by social isolation we have measured alpha 2- and beta-adrenoceptor binding in the cerebral cortex of rats isolated for 21 days starting immediately after weaning. After this period the animals showed a significant reduction in exploration in the elevated X-maze and increased avoidance of bright light in a two-compartment shuttlebox. There were no changes in adrenoceptor binding at this time, however. The implications of these findings are discussed.

Memory disturbance after stroke: frequency and associated losses

138 patients who survived an acute stroke had their memory assessed at 3 months. As a group these patients had no impairment of digit span when compared with published age-matched normal data. Immediate logical memory (of a story) was poor in 29 per cent, and 14 per cent could not draw a picture immediately after seeing it. Poor memory function was not associated with more severe strokes, but was associated with poor functional ability on everyday tasks. Poor visual recall was associated with lower abilities at ADL, independent of any effect of age. Statistically significant recovery was detected in immediate logical memory and visual recall between 3 and 6 months.

Identification of DNA sequences required for transcription of the human alpha 1-globin gene in a new SV40 host-vector system

We have developed a rapid and simple method for studying the transcription of cloned eucaryotic genes, which involves transfecting SV40-transformed monkey cell lines (COS cells) with derivatives of the plasmid pBR322 that contain the SV40 viral replication origin but lack regions necessary for viral transcription (SV-ORI vectors). Because COS cells produce SV40 T antigen and are permissive for SV40 viral replication, transfected SV-ORI plasmids replicate to a high copy number. SV-ORI plasmids carrying a human alpha-globin gene are also replicated in COS cells. Moreover, the alpha-globin gene is faithfully transcribed to produce high levels of RNA, which is accurately processed to produce authentic alpha-globin mRNA. We have used this transcription system to demonstrate that a sequence located between 55 and 87 base pairs upstream from the mRNA capping site is required for efficient transcription of the alpha-globin gene in COS cells.

Casting light on Darwin's ape at Queen's University

Images

New library buildings: Bracken Library, Queen's University, Kingston, Ontario, Canada

A brief sketch is given of the past history and present functions of the Bracken Library. Architectural and decorative features of the new library are described.

Cot deaths and water-sodium

Over a thirty-year period in Scunthorpe, during which there were two changes in the sodium content of the water supply, there were significantly more sudden deaths in infancy during the decade when sodium levels were highest. This is compatible with the hypothesis that hypernatraemia is a factor leading to cot death. Changes in the incidence of breastfeeding over the same period may have contributed to, but are unlikely to account for, the result because the pattern was different in a neighbouring district where there was no change in water quality.