Reduction of Cr(VI) by a Consortium of Sulfate-Reducing Bacteria (SRB III)

A consortium of bacteria with tolerance to high concentrations of Cr(VI) (up to 2,500 ppm) and other toxic heavy metals has been obtained from metal-refinishing wastewaters in Chengdu, People's Republic of China. This consortium consists of a range of gram-positive and gram-negative rods and has the capacity to reduce Cr(VI) to Cr(III) as amorphous precipitates which are associated with the bacterial surfaces. An endospore-producing, gram-positive rod and a gram-negative rod accumulate the most metallic precipitates, and, over time, 80 to 95% of Cr can be removed from concentrations ranging from 50 to 2,000 ppm (0.96 to 38.45 mM). Kinetic studies revealed a first-order constant for Cr removal of 0.1518 h -1 for an initial concentration of 1,000 ppm (19.3 mM), and the sorption isothermal data could be interpreted by the Freundlich relationship. The sorption was not entirely due to a passive interaction with reactive sites on the bacterial surfaces since gamma-irradiated, killed cells could not immobilize as much metal. When U or Zn was added with the Cr, it was also removed and could even increase the total amount of Cr immobilized. The consortium was tolerant to small amounts of oxygen in the headspace of tubes, but active growth of the bacteria was a requirement for Cr immobilization through Cr(VI) reduction, resulting in the lowering of E h . Our data suggest that the reduction was via H 2 S. This consortium has been named SRB III, and it may be useful for the bioremediation of fluid metal-refining wastes.

Maternity blues and major endocrine changes: Cardiff puerperal mood and hormone study II

OBJECTIVES

To define relation between mood and concentrations of progesterone and cortisol during perinatal period to test hypothesis that rapid physiological withdrawal of steroid hormones after delivery is associated with depression.

DESIGN

Prospective study of primiparous women from two weeks before expected date of delivery to 35 days postpartum.

SETTING

Antenatal clinic in university hospital, obstetric inpatient unit, patients' homes.

SUBJECTS

120 of 156 primiparous women interviewed. Remainder excluded because of major marital, socioeconomic, or medical problems or because caesarean section required.

MAIN OUTCOME MEASURES

Concentrations of progesterone and cortisol in saliva samples; women's moods assessed by various scores for depression.

RESULTS

Changes in salivary progesterone and cortisol concentrations were similar to those already characterised for plasma. Peak mean score for maternity blues (5.3 on Stein scale) was on day five postpartum (P < 0.02 compared with mean scores on other postpartum days). High postpartum scores for maternity blues were associated with high antenatal progesterone concentrations on day before delivery (P < 0.05), with high rate of rise of antenatal progesterone concentrations (P < 0.05), with decreasing progesterone concentrations from day of delivery to day of peak blues score (P > or = 0.01), and with low progesterone concentrations on day of peak blues score (P < 0.01). Seventy eight women were designated as having maternity blues (peak score > or = 8 on Stein scale) while 39 had no blues. Women with blues had significantly higher antenatal progesterone concentrations and lower postnatal concentrations than women without blues (geometric mean progesterone concentrations: one day before delivery 3860 pmol/l v 3210 pmol/l respectively, P = 0.03; ten days postpartum 88 pmol/l v 114 pmol/l, P = 0.048). Cortisol concentrations were not significantly associated with mood.

CONCLUSION

Maternal mood in the days immediately after delivery is related to withdrawal of naturally occurring progesterone.

Synthesis of benzo-fused benzodiazepines employed as probes of the agonist pharmacophore of benzodiazepine receptors

The synthesis and in vitro evaluation of benzo-fused benzodiazepines 1-6 are described. These "molecular yardsticks" were employed to probe the spatial dimensions of the lipophilic pocket L2 in the benzodiazepine receptor (BzR) cleft and to determine the effect of occupation of L2 with respect to agonist activity. Of the new analogs synthesized, the 7,8-benzo-fused benzodiazepine 6 displayed moderately high affinity for the BzR (IC50 = 55 nM) and exhibited both anticonvulsant (ED50 approximately 15 mg/kg) and muscle relaxant (ED50 approximately 15 mg/kg) activity. As expected, 2 and 4 interacted with the repulsive regions of interaction, S1 and S2, and exhibited low affinities for BzR. The rigid nature of these molecular yardsticks (especially 6, Figure 7) has been employed to probe the depth of L2. Moreover, in the case of 6 full occupation of L2 has resulted in an increase in the muscle relaxant effect at the expense of the anticonvulsant/anxiolytic effect.

Effects of undegradable protein and supplemental fat on milk yield and composition and physiological responses of cows

Because some previous studies indicated that addition of dietary fat may delay milk yield response and that effects carry over after withdrawal, an objective of this reversal design with four 28-d periods was to estimate residual effects. Diets were fed 2 wk before period 1 to permit inclusion of pretreatment diet in the mathematical model and changed for each of 33 cows at the start of periods 1 through 3; period 4 treatments continued those for period 3. Diets were 50% corn silage supplemented to be 12% CP with soybean meal and urea; 15% CP with soybean meal, blood and soybean meals, or feather and soybean meals; and 18% CP with soybean meal or blood and soybean meals. Protein treatments were replicated in diets containing 2.0% Ca soaps of fatty acids. No carry-over effects were significant; however, yield increases from Ca soaps were not evident until wk 4. Diet CP had a positive linear effect on milk and SCM yields, BW, and blood urea N. Milk protein percentage was higher from soybean meal diets. Addition of dietary Ca soaps of fatty acids increased milk, protein, fat, and SCM yields. Milk protein percentage was depressed when Ca soaps of fatty acids were fed with blood meal but not with soybean meal. No positive responses were observed from increasing dietary undegradable protein with blood meal or feather meal.

HIV prevention in prisons and jails: obstacles and opportunities

High rates of human immunodeficiency virus (HIV) infection among jail and prison inmates suggest that HIV prevention efforts should focus on incarcerated populations. Overcrowding, the high prevalence of injection drug use, and other high-risk behaviors among inmates create a prime opportunity for public health officials to affect the course of the HIV epidemic if they can remedy these problems. Yet, along with the opportunity, there are certain obstacles that correctional institutions present to public health efforts. The various jurisdictions have differing approaches to HIV prevention and control. Whether testing should be mandatory or voluntary, whether housing should be integrated or segregated by HIV serostatus, and whether condoms, bleach, or clean needles should be made available to the prisoners, are questions hotly debated by public health and correctional officials. Even accurate assessment of risk-taking within the institutions leads to controversy, as asking questions could imply acceptance of the very behaviors correctional officials are trying to prevent. Education and risk-reduction counseling are the least controversial and most widely employed modes of prevention, but the effectiveness of current prevention efforts in reducing HIV transmission in this high-risk population is largely undetermined.

Lineage analysis reveals neurotransmitter (GABA or glutamate) but not calcium-binding protein homogeneity in clonally related cortical neurons

Studies of cell lineage in the rat cerebral cortex have provided new insights into the mechanisms of neuronal and glial determination. They have shown that clonally related cells, marked with retrovirus injection at embryonic day 16 (E16), express the same glial or neuronal phenotype, suggesting that separate progenitors for each of these cell phenotypes exist in the ventricular zone at that stage of corticogenesis. However, it is not known if such committed progenitors are present in the ventricular zone before E16. Another important question concerns which neurochemical features are shared by clonally related cells of the adult cerebral cortex. In this study we have addressed the first question by injecting a retroviral vector expressing beta-galactosidase into the telencephalic ventricles of rat embryos at different stages (E14-E19). In order to classify clonally related neurons in the cerebral cortex of these rats, we have used postembedding immunohistochemistry for the amino acid neurotransmitters glutamate, aspartate, and GABA. Glutamate and GABA immunoreactivity marked nonoverlapping populations of cells that corresponded to the pyramidal and nonpyramidal neuron types of the rat cerebral cortex. Clonally related neurons, marked by retrovirus injection at any day between E14 and E19, homogeneously expressed one or other phenotype and accordingly displayed glutamate or GABA immunoreactivity. This finding indicates that committed progenitor cells for pyramidal and nonpyramidal neurons are present in the ventricular zone before E16. To investigate whether lineage dictates other features in clonally related neurons, we performed an immunohistochemical analysis for the calcium-binding proteins calbindin, parvalbumin, and calretinin in clusters of clonally related nonpyramidal neurons. The same calcium-binding protein was rarely found in members of the same cluster, suggesting that lineage does not control the expression of calcium-binding proteins in cortical nonpyramidal neurons. As a result of examining a large number of clonally related neurons from brains injected at different ages, we observed remarkable differences in number and laminar distribution of pyramidal and nonpyramidal neurons marked with retrovirus. Clusters of nonpyramidal neurons were usually composed of two or three cells, and resided in the cortical layers that were just being generated at the time of injection. Clusters of pyramidal neurons were larger and dispersed in several layers in the earlier injections; their size and laminar distribution were progressively reduced for later injections. These observations suggest the existence of different mechanisms that generate the pyramidal and nonpyramidal neurons of the cerebral cortex.

The demographic impact of the First World War: an anthropometric perspective

During the 1970s and 1980s Jay Winter published a series of highly influential articles on the demographic impact of the First World War, culminating in his study of The Great War and the British People in 1986. Winter argued that the war led to a dramatic improvement in average living standards, and that the survival chances of most sections of the civilian population improved more rapidly than they might have done if peace had been maintained. This paper seeks to test the strength of Winter's hypothesis in three main ways. Section I examines the arguments which Winter himself put forward to support his view that the war led to a systematic erosion of pre-war differentials in infant mortality. Section III utilizes evidence relating to children's heights to examine the extent to which the war led to improvements in children's 'nutritional status'. The paper's overall conclusion is that the war did not lead to any dramatic improvements in civilian health; the overall impression to be gained from an analysis of wartime health statistics is one of continuity rather than change.

Mesenteric lymphadenitis depicted by indium 111-labeled white blood cell imaging

An acutely ill child with abdominal pain and concomitant pharyngitis often presents a diagnostic challenge. This report describes how indium 111-labeled white blood cell imaging helped to clarify the confusing case of a 4-year-old boy with fever, pharyngitis, and abdominal pain. The triad of abnormal white cell localization in the nasopharynx, cervical lymph nodes, and right lower abdominal quadrant supported the diagnosis of a systemic infection rather than appendicitis, abscess, or another surgical condition. Mesenteric lymphadenitis associated with systemic infection should be included in the differential diagnosis of abdominal pain in a child with this clinical presentation.

Demographic characteristics of retroviral infections (HIV-1, HIV-2, and HTLV-I) among female professional sex workers in Lagos, Nigeria

In 1990/1991, 885 prostitutes residing in 11 of the 12 Local Government Areas (LGAs) of Lagos State, Nigeria, participated in a cross-sectional study to determine current seroprevalence of antibodies to human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2), and human T-cell lymphotropic virus type I (HTLV-I). The overall prevalence of HIV-1 was 12.3%, of HIV-2, 2.1%, and of HTLV-I, 2.8%. HIV-1 seropositivity did not vary significantly by age, socioeconomic class, or nationality, but HIV-1 seroprevalence was significantly elevated for prostitutes resident in the Port area of Lagos which serves as a crossroads for international and national commerce (OR = 2.3; 95% CI = 1.1, 4.6). HIV-2 infection was significantly associated with low socioeconomic class (OR = 3.7; 95% CI = 1.2, 10.8) and non-Nigerian nationality (OR = 6.7; 95% CI = 2.5, 18.4). Prevalence of HTLV-I infection increased significantly with age (OR = 2.3; 95% CI = 1.0, 5.3). The high seroprevalence of HIV-1 in this survey, compared with previous surveys reported in the last several years and the correlation between high prevalence and areas of international commerce suggest that HIV-1 is spreading in this area of Nigeria. Intensified prevention campaigns are needed to address this possible emerging epidemic.

A hormonal component to postnatal depression

Disorders of the thyroid gland are associated with disorders of mood (Thomas et al, 1970; Van Uitert & Russakoff, 1979; Folks, 1984; Young, 1984; Jadresic, 1990). Both hypothyroid and hyperthyroid states can be associated with depression, which is sometimes accompanied by psychotic features such as delusions and hallucinations (Wilson & Jefferson, 1986). Similarly, primary affective disorders can be accompanied by changes in thyroid function, with low thyroid-stimulating hormone (TSH) levels and elevated thyroxine (T4) (Kirkegaard & Faber, 1980), and in major depressive illness there is often a blunted TSH response to thyrotrophin releasing hormone (TRH) (Prange et al, 1972; Loosen, 1987).

Neurochemical actions of inhalational anesthetics at the GABAA receptor complex

Pharmacologically relevant concentrations of inhalational anesthetics such as halothane, enflurane and isoflurane enhance [3H]flunitrazepam (FLU) binding to benzodiazepine receptors prepared from well-washed membranes of murine cerebral cortex and cerebellum. These effects were concentration dependent and markedly enhanced by addition of chloride to the incubation medium. Using halothane as a prototype inhalational agent, it was observed that like barbiturates, increases in [3H]FLU binding were effected through an increase apparent in the apparent affinity of this radioligand with no accompanying change in the maximum number of binding sites. Although previous reports have demonstrated barbiturates augment gamma-aminobutyric acid-enhanced [3H]benzodiazepine binding, halothane exerts an additive effect in the nominal absence of chloride. Isoflurane produces a significant reduction in the EC50 of pentobarbital-augmented [3H]FLU binding. Halothane modestly reduced the binding of a benzodiazepine receptor inverse agonist, [3H]Ro 15-4513. Significant differences were also observed in the potencies and efficacies of both isoflurane and enflurane to enhance [3H]FLU binding to benzodiazepine receptors in cerebellar and cortical membranes. These findings provide a possible molecular basis for the clinical observation that benzodiazepines and barbiturates augment the anesthetic properties of inhalational agents. Moreover, the regional differences in anesthetic potency and efficacy reported here suggest a differential interaction of these inhalational agents among gamma-aminobutyric acidA receptor isoforms.

Load concentrations around crystal aggregates in articular cartilage under short-term loading

The deposition of crystals in joints is a feature of a number of joint diseases. Crystals are frequently observed on the surface of articular cartilage and in the mid-zone. The purpose of this investigation was to model the stress concentrations in the mid-zone of the cartilage layer arising from the presence of large crystal aggregates. Scanning electron microscopy was used to determine the geometry and distribution of crystal aggregates within the cartilage layer. Finite element and photoelastic approaches were then used to predict the stress distribution around spherical aggregates 50 and 100 microns in diameter. The implication of the results is that very densely packed and tightly bound spherical aggregates will themselves carry a certain amount of load. However, less tightly packed aggregates, perhaps interspersed with fibrous tissue, are potentially much more damaging.

Wear of articular cartilage: the effect of crystals

An investigation of the effect of crystals in a lubricant on the wear of articular cartilage in vitro was carried out in order to examine the hypothesis that crystals present in synovial fluid could cause abrasive damage of the articular surface. Plugs of cartilage were worn against a stainless steel counterface in a pin-on-disc wear rig. The concentration of cartilage debris present in the lubricant was assessed by measuring the bound sulphate originating from the glycosaminoglycans by ion chromatography. Results indicated that the presence of crystals in the lubricant significantly increased the concentration of wear debris and that the crystal size and morphology influenced the type of damage sustained by the cartilage. Other experimental evidence suggested that cartilage scratched in vivo was no more susceptible to further in vitro damage in this experimental model than normal cartilage. These results implied that crystals present in the synovial fluid of arthritic joints have the potential to cause excessive wear of the articular surface, but that if such crystals are removed the scratched cartilage may not be susceptible to any further damage by abrasive wear.

Basal cell carcinoma arising in venous ulcers and mimicking granulation tissue

BACKGROUND

Basal cell carcinoma (BCC) arising in venous ulcers is rare, and its appearance in this setting is not fully recognized.

OBJECTIVE

The purpose of this report is to alert the clinician to the subtle clinical appearance of this tumor and to prompt a more rapid recognition.

METHODS

We report five cases of BCC arising in venous ulcers of the lower extremity that we have observed over a period of 6 years. In all cases the tumor was diagnosed histologically.

RESULTS

In all five cases the tumor had the appearance of seemingly healthy granulation tissue, which was often exuberant and translucent. The border of this apparent "granulation tissue" was rolled over the margins of the ulcer.

CONCLUSION

Basal cell carcinoma arising in venous ulcers often has the appearance of translucent granulation tissue that extends beyond the ulcer's margins. These clinical characteristics should alert the clinician to the need for obtaining a biopsy of the ulcer bed.

Cardiff puerperal mood and hormone study. 1. Saliva steroid hormone profiles in late pregnancy and the puerperium: endocrine factors and parturition

Participants were 120 primiparous women who had vaginal delivery of a non-handicapped child. Saliva was collected twice daily through parturition to day 35 post-partum. In the prepartum, a highly significant circadian rhythm was seen in cortisol, with a lower-amplitude rhythm in progesterone (AM/PM = 1.12). Evening samples showed a rise in cortisol, with a highly significant rise on day -1. The rise was small. The fall in progesterone in the 3 days before parturition was also small (approximately 6%). Neither change provides an obvious trigger for parturition.

Health services in the New England region and their relevance to Aboriginal people

Public hospitals provide the vast majority of available health services in rural areas of Australia. These services reflect their clinical European origins in terms of organisation and delivery. This is one reason why they remain largely foreign and irrelevant to Aboriginal people, who are reluctant users of the services and facilities available. In this article we examine what is being done in the New England region of New South Wales to improve the relevance of existing health services for Aboriginal people; this is an important first step in improving the third world health status which they presently endure.

Effects of concentration of dietary phosphorus on amount and route of excretion

Objectives were to determine the effect of dietary concentration of P in DM on routes of excretion of P and to evaluate direct and indirect measures of calculating DM digestibility and P excretion. Twelve lactating Holstein cows were fed 20 kg of DM containing .41% P daily for 4 wk and then were assigned randomly to one of three diets: low (.30%), medium (.41%), or high (.56%) in P for 9 wk. Total collections of excreta (feces and urine) and milk were made during wk 4, 7, 10, and 13. At wk 4, cows excreted 88.2% of P consumed daily: 68.6% of excreted P in feces, 1.0% in urine, and 30.3% secreted in milk. Cows assigned to the low P diet decreased intake by 26.8% and excretion of P in feces by 22.7% in wk 13 compared with wk 4, whereas cows fed the high P diet increased intake by 36.5% and excretion of P in feces by 48.6%. Digestibility of DM was 62.6% when calculated from total collection of feces but only 55.7 or 56.5% when estimated indirectly using Cr or acid detergent lignin as indigestible markers. Apparent excretion of P was less than that estimated using either of the marker techniques (49.7 vs. 59.1 and 58.1 +/- .7 g/d of P) because digestibility of DM was underestimated. A prediction equation was developed for P excretion based on P intake and milk production.