Virus species polemics: 14 senior virologists oppose a proposed change to the ICTV definition of virus species

The Executive Committee of the International Committee on Taxonomy of Viruses (ICTV) has recently decided to modify the current definition of virus species (Code of Virus Classification and Nomenclature Rule 3.21) and will soon ask the full ICTV membership (189 voting members) to ratify the proposed controversial change. In this discussion paper, 14 senior virologists, including six Life members of the ICTV, compare the present and proposed new definition and recommend that the existing definition of virus species should be retained. Since the pros and cons of the proposal posted on the ICTV website are not widely consulted, the arguments are summarized here in order to reach a wider audience.     

Elevated risk of adverse obstetric outcomes in pregnant women with depression

In this study, we evaluated the association between prenatal depression symptoms adverse birth outcomes in African–American women. We conducted a retrospective cohort study of 261 pregnant African–American women who were screened with the Edinburgh Postnatal Depression Scale (EPDS) at their initial prenatal visit. Medical records were reviewed to assess pregnancy and neonatal outcomes, specifically preeclampsia, preterm birth, intrauterine growth retardation, and low birth weight. Using multivariable logistic regression models, an EPDS score ≥10 was associated with increased risk for preeclampsia, preterm birth, and low birth weight. An EPDS score ≥10 was associated with increased risk for intrauterine growth retardation, but after controlling for behavioral risk factors, this association was no longer significant. Patients who screen positive for depression symptoms during pregnancy are at increased risk for multiple adverse birth outcomes. In a positive, patient-rated depression screening at the initial obstetrics visit, depression is associated with increased risk for multiple adverse birth outcomes. Given the retrospective study design and small sample size, these findings should be confirmed in a prospective cohort study.     

The γ-Glutamyl Cycle: A Possible Transport System for Amino Acids

Evidence is presented that rat kidney contains enzymes that catalyze the synthesis and utilization of glutathione; these reactions, which involve the uptake and release of amino acids from gamma-glutamyl linkage, constitute a cyclical process which is termed "the gamma-glutamyl cycle." The gamma-glutamyl cycle has properties that fulfill the requirements of an amino acid transport system. Thus, gamma-glutamyl transpeptidase may function in translocation and gamma-glutamylcysteine synthetase and glutathione synthetase may catalyze energy-requiring "recovery" steps in transport. These and other considerations suggest that glutathione serves a carrier function in amino acid transport.     

Diabetes and female sexual dysfunction: Moving beyond "benign neglect"

Female sexual response is a complex, nonlinear progression from desire to arousal and orgasm. Diabetes may affect all these, but it particularly affects arousal with decreased genital sensation and lubrication. Vaginal dryness and infections may lead to dyspareunia. Predictors of sexual dysfunction in women include depression. Neither age, duration of diabetes, glycemic control, nor complications predict sexual dysfunction in women as they do in men. Objective measures of decreased genital sensation or lubrication do not correlate with a subjective sense of female sexual arousal disorder. Low androgens and possibly estrogens may be etiologic, as may numerous medications used by patients with diabetes. Practitioners should recognize the high prevalence of female sexual dysfunction (up to 50%) and potential increase, in tandem with that of diabetes. In the absence of definitive treatment evidence, psychological counseling, improvised vaginal lubricants, and low doses of estrogens or androgens have been used to relieve the personal distress of female sexual dysfunction.     

Metabolism of 1-14C-ornithine and 1,4-14C-putrescine in chronically uremic and control rats

The metabolism of ornithine and putrescine was studied in vivo in chronically uremic and control rats. Rats were injected intraperitoneally with 1-¹⁴C-ornithine or 1,4-¹⁴C-putrescine and expired ¹⁴CO₂ was collected for 4 hr. After injection of 1-¹⁴C-ornithine, ¹⁴CO₂ expiration was decreased in uremic rats as compared to controls. Conversely, after 1,4-¹⁴C-putrescine injection, expiration of ¹⁴CO₂ was increased in uremic rats as compared to controls. Four hours after the injection of 1-¹⁴C-ornithine, there was more radioactivity in liver and muscle and less radioactivity in kidney of uremic rats as compared to the respective sources in control rats. In uremic rats, 4 hr after the 1,4-¹⁴C-putrescine injection, the radioactivity retained in the muscle and plasma was greater than in corresponding sources in control rats; whereas the radioactivity retained in uremic liver and kidney was similar to that of control rats. The greater putrescine-derived radioactivity retained in uremic tissues reflects either the retention of injected tracer compounds, or retention or decreased catabolism of putrescine metabolites. From ¹⁴CO₂ expiration data obtained, it appears that ornithine catabolism is reduced while putrescine catabolism is increased in uremia.