Mismatched hemagglutinin and neuraminidase specificities in recent human H3N2 influenza viruses

The hemagglutinin (HA) of influenza viruses initiates infection by binding to sialic acid on the cell surface via alpha2,6 (human) or alpha2,3 (avian) linkage. The influenza neuraminidase (NA) can cleave both alpha2,3- and alpha2,6-linked sialic acids, but all influenza NAs have a marked preference for the non-human alpha2,3 linkage. Recent H3N2 influenza viruses have lost the ability to agglutinate chicken red blood cells. To determine if changes in HA specificity or affinity correlate with NA specificity or activity, we examined red cell binding and elution of a series of H3N2 viruses. We found that the NA activity of many influenza viruses does not release binding by their HA. In some egg-adapted strains, lack of elution correlates with low levels of viral NA activity, and these elute rapidly when bacterial NA is added. However, a Fujian-like virus, A/Oklahoma/323/03, does not elute by its own NA or with Vibrio cholerae sialidase, and it binds to red cells pre-treated with V. cholerae sialidase. It elutes after addition of the broad specificity Micromonospora viridifaciens sialidase. Human glycophorin inhibits A/Oklahoma/323/03 hemagglutination 6-fold better than fetuin. We conclude that specific forms of sialic acid are used as receptor by recent human H3N2 influenza viruses, perhaps involving branched alpha2,6 sialic acid or alpha2,8 sialic acid structures on O-linked carbohydrates. The virus itself has no O-linked glycans, so even though the NA is not able to cleave receptors on cells, the viruses will not self-aggregate. It will be important to monitor efficacy of neuraminidase inhibitors in case there are NA-resistant receptors in the human respiratory tract that allow the viruses to be less dependent on NA activity.     

Acute upper extremity flaccid paralysis in a 5 year old child secondary to enterovirus infection

The incidence of acute flaccid paralysis has been on a declining trend with the global efforts on eradication of polio virus. A few scattered clusters of acute flaccid paralysis associated with pathogens like enterovirus other than polio virus and flaviviruses have recently come to limelight. This is a case of acute onset flaccid paralysis of left upper extremity in a fully immunized 5 year old child in New York.     

Protein kinase C regulation of glycine and gamma-aminobutyric acid release in brain stem auditory nuclei

Protein kinase C (PKC) can regulate transmitter release in several brain areas. We determined if PKC could regulate the electrically evoked release of radiolabeled glycine (Gly) and gamma-aminobutyric acid (GABA) in dissected samples of several brain stem auditory nuclei, such as the major subdivisions of the cochlear nucleus (CN) and the main nuclei of the superior olivary complex (SOC). The PKC activators, phorbol 12,13-diacetate (PDA) or phorbol 12,13-dibutyrate (PDBu) (3 microM), elevated the release by 1.4- to 2.0-fold. The PKC inhibitor, Ro31-8220 (50 nM), did not alter the release in most of the tissues but blocked the stimulatory effects of PDA and PDBu. This suggested that PKC positively regulates glycinergic and GABAergic release in the sampled nuclei. In the dorsal CN (DCN), Ro31-8220 elevated the release of [(14)C]Gly by 23%, suggesting that PKC negatively regulates glycinergic release in a proportion of DCN synapses. We also determined if PKC could regulate release after unilateral cochlear ablation (UCA). In the anteroventral (AVCN) and posteroventral (PVCN) CN and in the lateral (LSO) and medial (MSO) superior olive, the stimulatory effects of PDBu declined after this lesion and Ro31-8220 failed to alter release. Since UCA failed to alter release in these tissues, the stability of the release correlated with the lack of regulatory capacity of PKC. In the DCN and the medial nucleus of the trapezoid body (MNTB), the stimulatory effects of PDBu persisted after UCA. We previously demonstrated a postablation decline of Gly release in the DCN and elevated GABA release in the MNTB. Treatment of these tissues with Ro31-8220 reversed these changes in release. These findings suggested that PKC regulation persisted in the DCN and MNTB after UCA. Moreover, endogenous regulatory mechanisms activated after UCA probably act through PKC to alter release in these tissues. Thus, limiting PKC activation or activity might ameliorate pathological symptoms that accompany hearing loss and that stem from these plasticities in the DCN and MNTB.     

Waiting times to see a dermatologist are perceived as too long by dermatologists: implications for the dermatology workforce

BACKGROUND: The issue of workforce requirements in dermatology has come to attention in recent years because it affects the delivery of dermatologic care in the United States. OBJECTIVE: To determine the waiting times for appointments with dermatologists in order to assess the adequacy of the current level of dermatology workforce. METHODS: Waiting times were determined for new and return patient appointments by telephone survey of a random sample of American Academy of Dermatology members. Physicians' perception of the adequacy of the number of dermatologists in their area was used as a criterion standard to validate waiting times as a measure of workforce adequacy. Benchmark waiting times of 3 weeks for a new patient appointment and 2 weeks for a return appointment were established. RESULTS: Physicians' estimates of the waiting time for a new patient appointment and their perceptions of the adequacy of the number of practicing dermatologists in their area were closely correlated (r = -0.65; P<.001), validating the use of waiting times as a measure of workforce adequacy. More than 60% of the dermatologists surveyed exceeded the criterion cutoff waiting times, and more than 42% of the US population lives in areas underserved by dermatologists. Dermatologists practicing in areas of higher population density were more likely to have shorter waiting times for new patient appointments and were more likely to include cosmetic dermatology in their practices. CONCLUSION: The long waiting times for appointments suggests that the current supply of dermatologists is not adequate to meet the demand for dermatologists' services.     

Estrogen replacement therapy and ovarian cancer

Estrogen replacement therapy (ERT) has been shown to be of benefit for menopausal women, especially in prevention of coronary heart disease and osteoporotic fractures. Cancer fear is an important obstacle to use of ERT. From our literature review, there is a weak or no association between ERT and ovarian cancer risk. Individual risk of cancer should be considered before ERT use. The second issue in this review is ERT in patients with ovarian cancer. The majority of patients with ovarian cancer are postmenopausal or become menopausal after surgery. ERT is considered by many physicians to be contraindicated in patients with cancer. However, there is evidence that ERT in selected cancer patients may be of benefit for survival and quality of life. After weighing the evidence from studies on ERT in patients with ovarian, breast or endometrial cancer, we propose the use of ERT in selected ovarian cancer patients who are suffering from or are at a high risk of debilitating menopausal symptoms, osteoporosis, and coronary heart disease. The benefit of ERT to selected patient's health and quality of life appears to outweigh the risk of cancer recurrence.     

Comparative study of Finn Chambers and T.R.U.E. test methodologies in detecting the relevant allergens inducing contact dermatitis

T.R.U.E. Test is a ready-to-use patch test system, which contains 23 allergens and is the only Food and Drug Administration-approved source of allergens currently commercially available in the United States. Previously, allergens dispersed in either petrolatum or water and designed to be applied utilizing Finn Chambers were also commercially available in the United States. During a 5-year study at the University of Kansas Medical Center, 167 patients were patch tested using both Finn Chamber and T.R.U.E. Test methodologies. Discordant positive reactions were examined for clinical relevance. The Finn Chamber methodology was superior in detecting clinically relevant allergies to fragrance mix, balsam of Peru, and thiuram mix. T.R.U.E. Test performed somewhat better than the Finn Chamber in detecting relevant allergic reactions to nickel, neomycin, and methylchloroisothiazolinone/methylisothiazolinone. Neither T.R.U.E. Test nor Finn Chamber methodologies performed optimally in detecting relevant allergies to formaldehyde and carbamates. Practitioners limited to only the T.R.U.E. Test methodology need to be aware that relevant reactions to fragrances, rubber accelerators/pesticides (carbamates and thiurams), and formaldehyde may be missed with this system.     

Effects of T-2 toxin gavage on the synthesis and contents of rat-liver macromolecules

Effects of oral administration of T-2 toxin (0.75 mg/kg body weight/day) for 7, 14 or 21 days on the liver and plasma of young male rats were studied. A significant decrease in body weight and an increase in liver weight were observed in rats treated with T-2 toxin. Liver protein and glycogen levels were significantly lower than in controls after 21 days of treatment, but no significant differences were observed after 7 or 14 days. Levels of RNA in liver were significantly increased after 7, 14 and 21 days of treatment whereas liver DNA levels were significantly lower than in controls at each time interval. Liver microsomal protein was significantly decreased after 14 and 21 days, but microsomal RNA contents were significantly increased at 7 days and significantly decreased at 21 days. The levels of serum protein at 7, 14 and 21 days and of blood glucose at 14 and 21 days were significantly lower in T-2 toxin-treated rats. The levels of incorporation of [14C]leucine and [3H]uridine into liver protein and RNA, and into liver microsomal protein and RNA, were higher than in controls at 7 days, but then decreased. The incorporation of [3H]thymidine into liver DNA was not significantly altered in animals treated with the toxin.     

Screening of antiplasmodial efficacy of <Emphasis Type="Italic">Ajuga bracteosa</Emphasis> Wall ex. Benth

The rising problem of Plasmodium resistance to the classical antimalarial drugs stresses the need to look for newer antiplasmodial components with effective and new mode of action. In the present study, the traditional medicinal plant Ajuga bracteosa has been screened for its antiplasmodial efficacy. The extract was found to possess significant in vitro antiplasmodial efficacy with an IC₅₀ of 10.0 μg/ml. Thus, the extract was further evaluated for its in vivo schizontocidal activity and efficacy in terms of survival time in Plasmodium berghei infected BALB/c mice. The extract at 250, 500, and 750 mg/kg/day exhibited significant (p < 0.0001) blood schizontocidal activity during established infection with enhanced mean survival time comparable to that of standard drug chloroquine, 5 mg/kg/day. The significant schizontocidal activity and enhanced mean survival time of mice stress the need to identify and characterize active antiplasmodial principle from this plant.