The genetic basis of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women of reproductive age. Familial clustering of cases suggests that genetic factors play an important part in its aetiology. A number of studies of families with several cases of PCOS have produced results suggesting an autosomal dominant trait. Detailed analysis of a large number of affected families has, however, cast some doubt about the mode of inheritance. An autosomal dominant trait remains possible but a more complex aetiology seems more likely. The results of our recent studies support the concept of an oligogenic disorder in which genes affecting metabolic pathways in glucose homeostasis and steroid biosynthesis are both involved. We review evidence for an important role for the insulin gene minisatellite in the aetiology of anovulatory PCOS and for the gene coding for P450 cholesterol side chain cleavage (CYP11a) in the mechanism of excessive androgen secretion in women with polycystic ovaries. We propose that the heterogeneity of clinical and biochemical features in PCOS can be explained by the interaction of a small number of key genes with environmental, particularly nutritional, factors.

Deletions at 11q identify a subset of patients with typical CLL who show consistent disease progression and reduced survival

Eighty-four patients with typical chronic lymphocytic leukemia (CLL) (by morphological and immunophenotypic criteria) on whom karyotypes were available were studied. Binet stage at diagnosis and follow-up were defined. Survival was calculated from diagnosis. Fifty-one percent of patients had a karyotypic abnormality, the commonest being abnormalities at 13q14 (16%); these patients did not have significantly different survival from patients with normal karyotype. The second commonest abnormality was del(11q) (13%); these patients had significantly worse survival when compared both with patients with normal karyotype (P < 0.0001) and with other patients with karyotypic abnormality (P = 0.0012). All patients with del(11q) had progressed to stage C at follow-up while only 20% of the other patients had shown any disease progression (P < 0.0001). Del(11q) may identify a subset of patients with typical CLL who have worse survival and consistent disease progression and in future may help define a group of patients with CLL who could benefit from earlier or more intensive therapy.

Electron probe microanalysis and transverse microradiography studies of artificial lesions in enamel and dentin: a comparative study

In cardiology and research involving the interactions between restorative materials and dental hard tissues, it is important for small changes in tooth mineral content to be measurable. Currently, transverse microradiography (TMR) is the most accepted tool for the above purpose. Electron Probe Microanalysis (EPMA) can yield both qualitative identification of elements and quantitative compositional information. The purpose of this study was to compare the mineral distribution in well-defined artificial lesions, in dentin and enamel, by the use of both TMR and EPMA on the same sample. The good correlation between the two sets of data validates EPMA as a technique and helps in the interpretation of its results. The data from TMR analysis are expressed as vol% of mineral, while EPMA gives the levels of Ca and phosphate in wt%. The conversion between the two sets of data is complicated by the fact that local density is, as yet, unknown.

p53 represses Sp1 DNA binding and HIV-LTR directed transcription

The HIV-LTR region contains binding sites for, and is regulated by, a number of transcription factors including Sp1 and NF-kB. The wild-type p53 tumor suppressor protein represses transcription from the HIV-LTR promoter while oncogenic mutant forms of p53 stimulate expression from the HIV-LTR. We have shown previously that wild-type p53 is a site specific DNA binding protein that binds to a region of the SV40 virus which contains GC-box DNA binding sites for the ubiquitously expressed transcription factor Sp1. In this study using DNase I footprinting, we have shown that purified p53 is able to protect the Sp1 binding sites and the adjacent NF-kB site of the HIV-LTR. Furthermore we have demonstrated that when p53 and Sp1 are mixed together both proteins change each other's interaction with DNA. Interestingly, we noted that oncogenic mutant p53 is also able to change the interaction of Sp1 with DNA. We confirmed p53 dependent repression of HIV-LTR driven transcription by comparing the expression from an HIV-LTR reporter construct in the presence and absence of p53. EMSA of an oligonucleotide sequence derived from the HIV-LTR sequence demonstrated a slight decrease in Sp1 DNA binding activity with nuclear extract derived from the cell line expressing a high level of wild-type p53. These data suggest that the influence of p53 on the transcription of promoters with Sp1 binding sites may be partially due to a change in the DNA binding ability of Sp1.

Estimating xenobiotic half-lives in humans from rat data: influence of log P

The nature of empirical allometric expressions relating dispositional and kinetic parameters for a given xenobiotic across multiple mammalian species is well known. It has also been demonstrated that a simple allometric relationship may be used to predict kinetic parameters for humans based merely on data for multiple xenobiotics from rats. We decided to explore reasons for the variance in the data arising from the latter method. We were particularly interested in learning whether any physicochemical characteristics of xenobiotics might account for outlying data points (i.e., poor prediction of human half-life from rat half-life). We have explored the influence of lipid solubility as reflected by a xenobiotic's log P value because adipose tissue comprises a significantly larger percentage of total body weight in humans than in rats. We used half-life data from the literature for 127 xenobiotics. A data subset of 102 xenobiotics for which we were able to find estimates of log P values, including several with extremely large log P values, was also analyzed. First and second order models, including and excluding log P, were compared. The simplest of these models can be recast as the familiar allometric relationship having the form Y = a(Xb). The remaining models can be seen as extensions of this relationship. Our results suggest that incorporation of log P into the prediction of xenobiotic half-life in humans from rat half-life data is important only for xenobiotics with extremely large log P values such as dioxins and polychlorinated biphenyls. Moreover, a second order model in logarithm of rat half-life accommodates all data points very well, without specifically accounting for log P values.

Electric current density imaging of bone by MRI

Current density imaging (CDI) has been shown to be a feasible method to map spatial distribution of electric currents through bone structures and for studying osteoporosis and bone fracture models. For the osteoporosis model, bone sample was moistened in a solution of a sodium salt of ethylendiamintetraacetic acid (EDTA) which causes chemical reaction with hydroxyapatite Ca2+ ions and lowers the mineralisation degree of the solid bone. This enables clear visualisation of conventional magnetic resonance imaging and CDI. Sensitivity of conventional magnetic resonance and CD images of bone was improved by immersing the bone samples into physiological saline containing contrast agent Gd-DTPA prior to imaging. To stimulate effects of bone fracture on electric current conductivity through bone, a transverse cut was made through the bone, and the resulting gap was filled with an insulator. Electric current density images under these conditions have shown that regions of strong conductivity can be distinguished from regions of no conductivity at the site where the insulator restricts electric current. Real bone fracture was imaged as well. To demonstrate influence of electrolyte concentration on electric current spatial distribution, the bone samples were imaged after being immersed in various saline concentrations. The same contrast in current density images was produced with the combinations of higher electrolyte concentrations and lower voltages. Our observations demonstrate the feasibility of the method in mapping current density in bone structures, which could have implications in understanding and monitoring the effects of the electrical stimulation.

Intravenous immunoglobulin in symptomatic and asymptomatic children with perinatal HIV infection

One hundred thirty-five children born to human immunodeficiency virus (HIV)-infected mothers were selected randomly to receive immunoglobulin (Gamimune-N, Miles Pharmaceutical Co) 200 mg/kg monthly for 1 year. All patients were seropositive by ELISA and Western blot at birth. At the time of the study, 15 symptomatic (P2) and 57 asymptomatic (P1) patients with evidence of viral infection (positive HIV culture or P24 antigen) received the immunoglobulin. Sixty-three indeterminate (PO) patients with no evidence of infection served as the control. Mean age for infants in group P2 was 32 months, 26 months for group P1, and 11 months for group PO. Significant reduction in the frequency of bacterial infections (ie, otitis media, upper respiratory tract infections, urinary tract infections, and acute gastroenteritis) was seen in the symptomatic group compared with both the asymptomatic and the control groups. Growth as measured by weight and height > 50th percentile was also markedly better in the symptomatic group than either asymptomatic or control patients. There was no significant difference in head circumference in all three groups. These results indicate that monthly intravenous immunoglobulin infusion (IVIG) appears to be beneficial to both symptomatic and asymptomatic HIV patients in reducing the frequency of bacterial infection and also enhancement of the immune response. However, symptomatic patients responded much better than the asymptomatic patients.

A prospective randomized evaluation of the prophylactic use of low-dose dopamine in cancer patients receiving interleukin-2

The administration of high-dose interleukin-2 (IL-2) causes tumor regression in 17-25% of patients with metastatic melanoma or renal cell carcinoma. Renal dysfunction is a common dose-limiting toxicity of IL-2 administration, limiting 26% of treatment cycles. We have conducted a prospective randomized trial to evaluate whether the prophylactic administration of low-dose dopamine (2 mg/kg/min) can minimize renal toxicity and thus affect the amount of IL-2 administered. Forty-two patients were randomly assigned to receive systemic high-dose IL-2 with standard supportive measures (group A = 21 patients) or with the addition of prophylactic dopamine (group B = 21 patients) at 2 mg/kg/min. For patients in group B, dopamine was instituted 1 h before the initiation of IL-2 administration and was discontinued 6-12 h after the maximum number of doses of IL-2 were given. There was no difference in the amount of IL-2 administered for each course of therapy for groups A and B. Despite differences in urine flow (milliliters per kilogram per day), fluid balance (liters per day), and overall weight gain, prophylactic low-dose dopamine did not significantly alter maximum plasma urea or creatinine levels in group B when compared with the control group (group A). The overall toxicity profile considering all grade 3 and 4 toxicities for patients in groups A and B was comparable. Thus, there is no evidence to support the routine use of prophylactic low-dose dopamine in patients receiving high-dose IL-2.

Effect of testosterone administration on sexual behavior and mood in men with erectile dysfunction

This double-blind placebo controlled, cross-over study was carried out to assess the effect of testosterone administration on sexual behavior mood, and psychological symptoms in healthy men with erectile dysfunction. Biweekly injections of 200 mg of testosterone enanthate were given over a period of 6 weeks separated by a washout period of 4 weeks. Blood samples for hormonal assessment, behavioral and psychological ratings were obtained prior to each injection. Luteinizing hormone remained significantly depressed but circulating testosterone had returned to baseline levels by 2 weeks following each hormonal injection. The ejaculatory frequency during the testosterone phase was statistically higher than during the placebo phase. There were marked, although statistically nonsignificant, increases in median frequency of reported sexual desire, masturbation, sexual experiences with partner, and sleep erections during the testosterone period. Testosterone did not have demonstrable effects on ratings of penile rigidity and sexual satisfaction. Mood variables and psychological symptoms did not change following hormonal administration. Results suggest that androgen administration to eugonadal men with erectile dysfunction may activate their sexual behavior without enhancing erectile capacity and without effects on mood and psychological symptoms.

Linkage and association of insulin gene VNTR regulatory polymorphism with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine disorder affecting up to 10% of women of reproductive age. Women with anovulatory PCOS have hyperinsulinaemia, insulin resistance, and dyslipidaemia, and the syndrome is associated with greatly increased risks of non-insulin-dependent diabetes mellitus and cardiovascular disease and it often clusters in families. The VNTR (variable number of tandem repeats) locus upstream of the insulin gene (INS) regulates insulin expression. We have studied INS VNTR as a candidate genetic locus for susceptibility to PCOS.

METHODS

We evaluated linkage of PCOS to the INS VNTR locus on chromosome 11p15.5 in 17 families with several cases, and looked for an association between VNTR and PCOS in two additional clinic populations. VNTR genotypes were designated I/I, I/III, and III/III and linkage disequilibrium mapping was used to test the primary role of the VNTR.

FINDINGS

In a group of PCOS/male pattern baldness families, we obtained positive evidence for linkage to 11p15.5 (p = 0.002). The INS VNTR III/III genotype was associated with an increased risk of PCOS in two independent case-control studies (odds ratios 8.20 [p = 0.005] and 5.70 [p = 0.043]). Multilocus linkage disequilibrium mapping suggests that VNTR itself is the predisposing locus.

INTERPRETATION

Mapping of susceptibility to PCOS to the INS VNTR implies that PCOS is due, in part, to an inherited alteration in insulin production. The data suggest a mechanistic link between type 2 diabetes and PCOS, which is a risk factor for diabetes later in life.

Association of the steroid synthesis gene CYP11a with polycystic ovary syndrome and hyperandrogenism

Biochemical data implicate an underlying disorder of androgen biosynthesis and/or metabolism in the aetiology of polycystic ovary syndrome (PCOS). We have examined the segregation of the genes coding for two key enzymes in the synthesis and metabolism of androgens, cholesterol side chain cleavage (CYP11a) and aromatase (CYP19), with PCOS in 20 multiply-affected families. All analyses excluded CYP19 cosegregation with PCOS, demonstrating that this locus is not a major determinant of risk for the syndrome. However, our results provide evidence for linkage to the CYP11a locus (NPL score = 3.03, p = 0.003). Parametric analysis using a dominant model suggests genetic heterogeneity, generating a maximum HLOD score of 2.7 (alpha = 0.63). An association study of 97 consecutively identified Europids with PCOS and matched controls demonstrates significant allelic association of a CYP11a 5' UTR pentanucleotide repeat polymorphism with hirsute PCOS subjects (p = 0.03). A strong association was also found between alleles of this polymorphism and total serum testosterone levels in both affected and unaffected individuals (p = 0.002). Our data demonstrate that variation in CYP11a may play an important role in the aetiology of hyperandrogenaemia which is a common characteristic of polycystic ovary syndrome.

Effects of an ACE inhibitor combined with a calcium channel blocker on progression of diabetic nephropathy

It is clear that angiotensin-converting enzyme (ACE) inhibitors slow progression of diabetic nephropathy to a greater extent than other antihypertensive agents when blood pressure (BP) is reduced to levels below 140/90 mm Hg. Recent studies also demonstrate that nondihydropyridine calcium channel blockers (NDCCBs) slow progression of diabetic nephropathy in people with pre-existing renal insufficiency secondary to non-insulin dependent diabetes mellitus. The combined effects of both a CCB and ACE inhibitor have recently been examined in both animal models of diabetes as well as patients with established diabetic nephropathy. These studies demonstrate the following points: (a) at comparable BP levels, a combination of an ACE inhibitor with a NDCCB result in a greater reduction in proteinuria when compared to either components alone; and (b) conversely, addition of an ACE inhibitor to a dihydropyridine CCB (DCCB) yields effects on proteinuria similar to the ACE inhibitor alone. Therefore, addition of an ACE inhibitor to a DCCB demonstrates protection against the effects of DCCB alone. Addition of an ACE inhibitor to a NDCCB does not potentiate the preservation of renal morphology associated with progression of diabetic nephropathy when compared to either of its components alone. Conversely, a DCCB/ACE inhibitor combination yields morphologic results similar to the ACE inhibitor alone. Taken together these results suggest that ACE inhibitors when combined with a NDCCB result in greater reductions in proteinuria, and similar preservation of renal morphology when compared to either of its components alone.

Phylogenetic distribution of the global regulatory gene csrA among eubacteria

The gene csrA encodes a unique kind of global regulator, CsrA, which modulates glycolysis, gluconeogenesis, glycogen biosynthesis and glycogen catabolism in Escherichia coli. Southern hybridization and nucleotide sequencing data have revealed apparent csrA homologs within several families of the alpha and gamma subdivisions of the proteobacteria (purple bacteria) and in the Gram-positive bacterium Bacillus subtilis. Thus, the CsrA regulatory system appears widely distributed among eubacteria.

Moderating binge drinking: it is possible to change behaviour if you plan it in advance

Recent theories of enactment suggest that behaviour change is increased by planning how, where, and when to execute a behavioural response. Drawing on these theories, a brief planning intervention was designed and its effectiveness compared to an information-based health promotion programme (control). All participants were given information about the safe limits per drinking occasion and the adverse consequences of binge drinking, and were asked to drink within the safe limits in order to avoid these consequences. In addition, participants in the planning group received an option menu of possible responses for refusing a drink, asked to choose one strategy and specify a time and place in which the chosen strategy would be implemented. The planning intervention group did not differ from the control group on reported likelihood of future binge drinking, nor on levels of past drinking, age and gender. At a 2-week follow-up, members of the planning intervention group reported lower drinking frequency than controls. The implications of prior planning for interventions aimed at reducing alcohol-related harm are discussed.

Spontaneous de-differentiation correlates with extended lifespan in transformed thyroid epithelial cells: an epigenetic mechanism of tumour progression?

Normal thyroid follicular cells, like many highly differentiated epithelia, have limited proliferative capacity. We previously showed that this could be extended by expression of the SV40 large T oncogene, but that immortal lines always lost thyroid-specific differentiation. Detailed analysis now show that clones expressing T undergo 2 mutually exclusive fates. They either (i) remain well-differentiated, in which case they undergo irreversible growth arrest after 5 to 15 p.d., or (ii) spontaneously develop poorly differentiated sub-clones that exhibit greatly extended proliferative life spans (up to 75 p.d.). The frequency of this event (> 3 per 10(4) cell divisions) greatly exceeds that expected from somatic mutation, suggesting an epigenetic basis. This is supported by our finding of rare de-differentiated epithelial cells in normal thyroid that all generate clones with extended life spans, indistinguishable from the above, following introduction of SV40 T. Escape from early mortality in differentiated thyroid epithelium therefore requires not only loss of tumour suppressor gene function (induced here by SV40 T), but also a switch in differentiation programme, with the latter effectively converting the follicular cell into a cell type with increased intrinsic proliferative potential. The analogy between this in vitro model and the progression of thyroid cancer from the well-differentiated to the highly aggressive, anaplastic form suggests that de-differentiation may play a causal rather than a passive role in this critical switch in tumour behaviour.

Education and training of occupational therapists for neonatal intensive care units

OBJECTIVE

The neonatal intensive care unit (NICU) is an area in which occupational therapists require specialized advanced training and skills. The purpose of this study was to evaluate the nature of current practice among occupational therapists in NICU settings, their training, and their opinions regarding educational experiences necessary for NICU work.

METHOD

One hundred seventy-four NICU occupational therapists completed a survey questionnaire designed to elicit information about these issues.

RESULTS

The majority of respondents were engaged in similar practice duties in NICUs, most of which had been using therapy services for less than 10 years. Most of the respondents (83%) reported that their primary source of training was on the job rather than through formal course work or training programs. Many of the respondents (40%) lacked training in the use of any infant assessments, and 50% had 2 years or less of pediatric work experience before entering practice in the NICU. The respondents indicated that mentored experience, on-the-job training, pediatric work experience, extended continuing education courses, and formal internships could prove helpful to future occupational therapists who wish to acquire the knowledge and skills to become competent in the NICU.

CONCLUSION

Results of the survey indicate that current training and education to work in an NICU is inadequate and needs to be addressed. Occupational therapists working in NICUs desire and express the need for specialized training to work in this practice area. A more aggressive effort toward standard NICU education and training is necessary to ensure that occupational therapists are competent members of the NICU team.

Gliding motility in slide cultures of Myxococcus xanthus in stable and steep chemical gradients

A method was devised to construct stable and steep chemical gradients in slide cultures to study the movements of gliding cells. The movement of Myxococcus xanthus individual cells and small swarms was studied in these gradients. There was no response to gradients of Casitone and yeast extract that were previously reported to stimulate a positive chemotactic response with M. xanthus.