Growth hormone replacement therapy is not associated with retinal changes

GH and/or growth factors are thought to play a role in the pathogenesis of diabetic retinopathy. In addition, the occurence of retinal changes mimicking diabetic retinopathy in two GH-deficient (GHD) patients receiving GH replacement therapy (GHRT) has recently been reported. The present study was performed to evaluate whether this was a coincidence or whether GHRT might regularly induce retinal changes. Sixty-one GHD patients on GHRT with a mean age of 42.5 +/-17.3 yr were examined by one ophthalmologist (AR). The mean duration of GHRT was 8.4 +/- 3.7 yr in childhood onset and 3.5 +/- 2.1yr in adult onset patients. Plasma insulin-like growth factor I concentrations were 76.4 +/- 49.6 ng/mL before GHRT and 244.3 +/- 119.2 ng/mL while receiving GHRT with a dose of 1.7 +/- 0.7 IU/day. After pupil dilatation with tropicamide, fundus examinations of both eyes were performed using a Volk 90 diopter fundus lens with a slit lamp (Haag Streit, Bern, Switzerland). In none of the patients were vascular or retinal changes like macular edema, microaneurysms, hemorrhages, hard exsudates, cotton wool spots, preproliferative signs, or proliferations found. The optic discs were also normal in all patients. We conclude, therefore, that long-term GHRT can be administered safely in GHD patients without an increased risk of retinal changes.

Plasma acylation stimulating protein, adipsin and lipids in non-obese and obese populations

BACKGROUND

Acylation stimulating protein (ASP) is a potent stimulator of TG synthesis in human adipocytes.

DESIGN

In the present study, we have analysed plasma ASP and adipsin levels and their relationships to plasma lipids in non-obese and obese groups.

RESULTS

The results show that the frequency distribution of ASP is skewed but that of adipsin is normal in both groups. In the non-obese population, the mean levels of plasma ASP and adipsin were 20.2 nmol L-1 (median) and 66.6 +/- 19 nmol L-1 (mean) respectively. No difference was observed between men and women for each of the parameters. In the obese population, the median plasma ASP was increased by 246% (69.9 nmol L-1) and adipsin by 31% (87.0 +/- 22.7 nmol L-1) above that of the control group. Although the levels for men and women were not statistically different for adipsin, the median ASP plasma concentration was 1.9-fold higher in obese women than in obese men (71.8 nmol L-1 vs. 37.6 nmol L-1, P < 0.05). Best subset regression analysis provided a model with variables that best predict plasma ASP [r2 = 0.160, P < 0.008 for body mass index (BMI), P < 0.05 for triacylglycerol (TG), P < 0.03 for free fatty acid (FFA)] and plasma adipsin (r2 = 0.057, P < 0.017 for BMI) in a non-obese population. In obese subjects, the model was different for plasma ASP (P = NS for any of the variables) and plasma adipsin (r2 = 0.356, P < 0.008 for FFA, P < 0.0002 for BMI, P < 0.02 for age). There was no correlation between ASP and adipsin in either the non-obese or the obese group.

CONCLUSION

The present data suggest involvement of the ASP/adipsin pathway in the pathogenesis of obesity.

Human pre-mRNA cleavage factor Im is related to spliceosomal SR proteins and can be reconstituted in vitro from recombinant subunits

Four polypeptides of 25, 59, 68, and 72 kDa copurify with the activity of human cleavage factor Im (CF Im) involved in pre-mRNA 3' end processing. We report here the cloning of the 25 and 68 kDa subunits and the reconstitution of functional CF Im25/68 from these two polypeptides. Several lines of evidence indicate that CF Im exists in at least two different forms. The 68 kDa polypeptide has a domain organization reminiscent of spliceosomal SR proteins. Analysis of the kinetics of the cleavage reaction indicates that interaction of CF Im with the RNA is one of the earliest steps in the assembly of the 3' end processing complex and facilitates the recruitment of other processing factors.

Impact of transfusion of mediastinal shed blood on serum levels of cardiac enzymes

BACKGROUND

Infusion of shed mediastinal blood using an autotransfusion system is a widely applied technique of blood conservation in cardiac surgery. Serial determinations of serum creatine kinase (CK), its MB isoenzyme (CK-MB), and lactate hydrogenase (LDH) levels have been used to monitor perioperative myocardial injury. We investigated the impact of postoperative autotransfused blood infusion on serum levels of these enzymes.

METHODS

We performed a retrospective analysis of postoperative serum CK, CK-MB, and LDH levels of 300 patients who had elective uncomplicated aortocoronary bypass grafting. Shed mediastinal blood samples from 26 patients were analyzed for CK, CK-MB (enzymatic activity and mass), and LDH levels before infusion.

RESULTS

High postoperative serum levels of CK and LDH were observed after infusion of autotransfused blood. Shed mediastinal blood contained extremely high levels of these enzymes, particularly from patients who had internal mammary artery dissection. There was a strong correlation (r = 0.96) between measured CK-MB enzyme activities and those calculated from the CK-MB mass units.

CONCLUSIONS

Infusion of autotransfused blood containing high concentrations of CK and LDH results in elevated serum levels of these enzymes. Hemolysis, frequently present in shed blood, does not interfere with the routine biochemical assays for CK and CK-MB enzyme activities. Caution should be taken when postoperative cardiac enzyme levels are used to determine myocardial injury after aortocoronary bypass grafting if autotransfusion is used as a method of blood conservation.

Understanding medication-related needs of low-literacy patients

An important thrust in preparing pharmacy students to provide pharmaceutical care is acquiring sensitivity to the unique medication-related needs of at-risk patient populations. Low literacy, which affects 21% to 23% of the American population, defines one such population. In collaboration with the Lafayette Adult Reading Academy (LARA), the authors developed an evolving project to increase pharmacy studies' understanding of the medication-related needs and perspectives of low-literacy patients. This was accomplished through a relation-building, three-step oral interview process. The interviewers asked open-ended questions to assess each patient's medication use habits and perspectives. The interview sensitized the pharmacy students to the needs of low-literacy patients for pharmaceutical care. The principal finding was that a caring relationship between pharmacists and patients is prerequisite to patients' openness to share and receive advice about problems and misconceptions associated with their medication use experiences.

Isolation of genomic and cDNA clones encoding bovine poly(A) binding protein II

cDNA clones for bovine poly(A) binding protein II (PAB II) were isolated. Their sequence predicts a protein of 32.8 kDa, revising earlier estimates of molecular mass. The protein contains one putative RNA-binding domain of the RNP type, an acidic N-terminal and a basic C-terminal domain. Analyses of authentic PAB II were in good agreement with all predictions from the cDNA sequence except that a number of arginine residues appeared to be post-translationally modified. Poly(A) binding protein II expressed in Escherichia coli was active in poly(A) binding and reconstitution of processive polyadenylation, including poly(A) tail length control. The cDNA clones showed a number of potential PAB II binding sites in the 3' untranslated sequence. Bovine poly(A)+RNA contained two mRNAs hybridizing to a PAB II-specific probe. Analysis of a genomic clone revealed six introns in the coding sequence. The revised molecular mass led to a demonstration of PAB II oligomer formation and a reinterpretation of earlier data concerning the protein's binding to poly(A).

Comparison of the short term efficacy and tolerability of lovastatin and simvastatin in the management of primary hypercholesterolemia

OBJECTIVES

To compare the safety and efficacy of lovastatin and simvastatin in patients with primary hypercholesterolemia.

METHODS

Fourteen Canadian centres participated in this double-blind, randomized, parallel-design study with a six-week screening period, a four-week placebo baseline period and an 18-week active treatment period. Patients were included in the study if their total cholesterol (TC) was at least 6.2 mmol/L and total triglycerides (TG) were 4.0 mmol/L or less at baseline. Half of the patients were in stratum I (TC 6.2 to 7.8 mmol/L at baseline and placebo period) and half in stratum II (TC greater than 7.8 mmol/L). The initial dose of lovastatin or simvastatin (20 and 10 mg/day, respectively) was doubled if the patient's cholesterol was greater than 5.2 mmol/L after six and/or 12 weeks, to a maximum of 80 mg/day lovastatin or 40 mg/day simvastatin. Of 298 randomized patients, two had baseline data only (and were excluded from the efficacy analysis), while 77 were treated with lovastatin and 74 with simvastatin in stratum I, and 72 were on lovastatin and 75 on simvastatin in stratum II.

RESULTS

In stratum I, both lovastatin and simvastatin lowered TC (-26.0% in both the lovastatin and simvastatin groups), low density lipoprotein (LDL) cholesterol (-33.4% in lovastatin and -34.4% in simvastatin), TG (-11.4% in lovastatin and -16.2% in simvastatin), apolipoprotein (apo)-B (-24.8% in lovastatin and -26.3% in simvastatin) and the TC:high density lipoprotein (HDL) cholesterol ratio (from 6.65 to 4.73 in lovastatin and from 6.45 to 4.46 in simvastatin), and increased HDL cholesterol (+3.6% in lovastatin and +7.8% in simvastatin) and apo-A1 (+6.3% in lovastatin and +9.0% in simvastatin) with P < 0.001 in all within-group tests except for HDL cholesterol (P < 0.05). Similar results were obtained in stratum II for TC (-30.7% in lovastatin and -30.3% in simvastatin), LDL cholesterol (-37.6% in lovastatin and -36.8% in simvastatin), TG (-21.9% in lovastatin and -16.9% in simvastatin), apo-B (-32.0% in lovastatin and -31.7% in simvastatin), TC:HDL cholesterol ratio (from 8.62 to 5.47 in lovastatin and from 8.96 to 5.77 in simvastatin), HDL cholesterol (+9.7% in lovastatin and +7.5% in simvastatin) and apo-A1 (+7.2% in lovastatin and +8.8% in simvastatin), with P < 0.001 in all within-group tests. Serious adverse events (clinical and laboratory) were reported in four patients in the lovastatin group and three in the simvastatin group. The most reported nonserious adverse effects were gastrointestinal tract (15 patients in the lovastatin group and 16 in the simvastatin group) and musculoskeletal (14 patients in the lovastatin group and 11 in the simvastatin group). Medication was withdrawn in eight patients.

CONCLUSIONS

Both lovastatin and simvastatin were found to be effective and well tolerated in each stratum. However, there were no significant differences between lovastatin and simvastatin in the treatment of moderate or severe primary hypercholesterolemia.

In vivo microscopy of the cerebral microcirculation using neonatal allografts in hamsters

Studies were performed to characterize the morphology and vascular reactivity of the allografted cerebral microcirculation. Cerebral cortical tissue was allografted into the cheek pouch of the hamster so that cerebral parenchymal vessels could be studied. The vascular morphology was characterized by a large number of looping vessels. The ultrastructural examination indicated viable cerebral tissue containing typical vessels, that is, "tight" junctions, not like those of the cheek pouch. Also, the microvasculature was impermeable to 150, 70, and 20 kDa fluorescein isothiocyanate dextrans. Angiotensin II and norepinephrine caused constriction of the cerebral vessels whereas adenosine caused dilation. Isoproterenol did not affect cerebral arterioles; however, it dilated cheek pouch arterioles. Thus, this preparation provides a satisfactory model for studying the living cerebral microcirculation.

Transport of proteins to the mitochondrial intermembrane space: the ‘matrix-targeting’ and the ‘sorting’ domains in the cytochrome c1 presequence

We reported earlier that the yeast cytochrome c1 presequence (length: 61 amino acids) directs attached proteins to the mitochondrial intermembrane space and that it appears to contain two functional domains: a 'matrix-targeting' domain, and a 'sorting' domain. We have now used gene manipulation together with two different in vivo import assays to map these two domains within the cytochrome c1 presequence. The 'matrix-targeting' domain is contained within the N-terminal 16 residues (or less); by itself, it directs attached proteins to the matrix. The 'sorting' domain extends into the C-terminal 13 residues of the presequence; while it does not mediate intracellular protein transport by itself, it acts together with the preceding 'matrix-targeting' sequence in sorting attached proteins into the intermembrane space. On replacing the authentic 'matrix-targeting' sequence with artificial sequences of different lengths we found that sorting of proteins between the outer membrane and the intermembrane space is not exclusively determined by the length of the N-terminal 'matrix-targeting' sequence.

TSH and prolactin responses to TRH in patients with premenstrual syndrome

The thyroid-stimulating hormone (TSH) and prolactin responses to thyrotropin-releasing hormone (TRH), administered during the follicular and luteal phases of the menstrual cycle, were examined in 14 women with prospectively confirmed premenstrual syndrome and in nine control subjects. There were no differences in basal or maximum increase in TSH or prolactin values between menstrual cycle phases in patients or in control subjects or between patients and control subjects in either phase. However, there was significantly greater variability in TSH response to TRH among symptomatic patients (seven of 10 patients: three with blunted and four with augmented response) than among control subjects (none of nine patients).

Residual androgen binding in testicular feminization (TFM)

Most mutants with genetic androgen-resistance possess some level of androgen binding which exhibits properties of receptors. The present studies aim to determine whether the androgen binding activities in mutants are, or are related to, receptors. This binding portion is termed residual androgen receptors. We have examined several androgen-resistance mutants with testicular feminization (TFM). Putative androgen receptors from mice, rats, and humans with TFM have been compared, and at least three different types of residual receptors have been observed. They are discussed in relation to possible receptor defects and to differences in the nature of androgen-resistance associated with each of them.