Spatial, ontogenetic and interspecific variability in stable isotope ratios of nitrogen and carbon of Merluccius capensis and Merluccius paradoxus off South Africa.

General linear models (GLMs) were used to determine the relative importance of interspecific, ontogenetic and spatial effects in explaining variability in stable isotope ratios of nitrogen (δ(15) N) and carbon (δ(13) C) of the co-occurring Cape hakes Merluccius capensis and Merluccius paradoxus off South Africa. Significant GLMs were derived for both isotopes, explaining 74 and 56% of observed variance in Merluccius spp. δ(15) N and δ(13) C, respectively. Spatial effects (west or south coast) contributed most towards explaining variability in the δ(15) N model, with Merluccius spp. off the west coast having higher (by c. 1.4‰) δ(15) N levels than Merluccius spp. off the south coast. Fish size and species were also significant in explaining variability in δ(15) N, with both species showing significant linear increases in δ(15) N with size and M. capensis having higher (by c. 0.7‰) δ(15) N values than M. paradoxus. Species and coast explained most and similar amounts of variability in the δ(13) C model, with M. capensis having higher (by c. 0.8‰) δ(13) C values than M. paradoxus, and values being lower (by c. 0.7‰) for fishes off the west coast compared with the south coast. These results not only corroborate the knowledge of Merluccius spp. feeding ecology gained from dietary studies, in particular the ontogenetic change in trophic level corresponding to a changing diet, but also that M. capensis feeds at a slightly higher trophic level than M. paradoxus. The spatial difference in Merluccius spp. δ(15) N appears due to a difference in isotopic baseline, and not as a result of Merluccius spp. feeding higher in the food web off the west than the south coast, and provides new evidence that corroborates previous observations of biogeographic differences in isotopic baselines around the South African coast. This study also provides quantitative data on the relative trophic level and trophic width of Cape hakes over a large size range that can be used in ecosystem models of the southern Benguela.

Phosphonomycin, a new antibiotic produced by strains of streptomyces.

Phosphonomycin is a newly discovered antibiotic produced by streptomycetes. It is effective, when administered by the oral route, to mice infected with Gram-positive or Gram-negative microorganisms. The antibiotic is bactericidal and inhibits cell-wall synthesis.

Subcellular calcium pools of ischaemic and reperfused myocardium characterised by electron probe.

OBJECTIVE: The subcellular redistribution of calcium and other electrolytes was analysed in myocardium subjected to global ischaemia and reperfusion in order to establish possible causes of reperfusion injury. METHODS: Isolated ferret papillary muscles (maintained at 37 degrees C, 1.2 Hz stimulation) were exposed to ischaemic conditions for 1 h by isolating from room air, removing buffer, and exposing to a constant flow of water-saturated 95% N2/5% CO2 gas. Some muscles were "reperfused" for 5 min by exposing to control buffer. Electron probe microanalysis was used to measure subcellular electrolyte content. RESULTS: Ischaemia caused severe swelling and doubling of cell sodium [84(SEM 5) to 156(9) mmol.kg-1 dry weight (dw), P < 0.05]. Mitochondrial electrolyte concentrations were generally increased, most notably calcium [0.40(0.15) to 1.99(0.32) mmol.kg-1 dw, P < 0.05]. Electrolytes in other structures were more moderately affected. Reperfusion resulted in two general myocyte populations. Irreversibly injured cells exhibited contracture knots and an influx of extracellular fluid. Analysis was restricted to moderately injured cells, which had reduced swelling and varying numbers of vacuolated mitochondria. In the moderately injured cells, sodium remained high [167(11) mmol.kg-1 dw] and magnesium had increased from 39(2) to 52(2) mmol.kg-1 dw (P < 0.05). Mitochondrial calcium was near control levels [0.64(0.42) mmol.kg-1 dw]. Junctional sarcoplasmic reticular calcium significantly increased [6.56(0.59) to 18.53(1.64) mmol.kg-1 dw in control and reperfused cells, respectively, P < 0.05], while calcium had not changed significantly in T tubule lumen or "3rd compartment", composed of sarcoplasmic reticulum, T tubules, and free sarcoplasm. "3rd compartment" and junctional sarcoplasmic reticulum results suggest that sarcolemma bound calcium had decreased. CONCLUSIONS: Surviving myocytes had no change in total calcium, but showed a large degree of calcium redistribution. Mitochondria accumulated calcium during ischaemia, but released it upon reperfusion. Sarcoplasmic reticulum in reperfused cells appeared functional and may have helped maintain physiological [Ca2+]i by storing calcium released from mitochondria and the sarcolemma. Mitochondrial and sarcolemmal damage are proposed as critical factors in reperfusion injury.

Calcium displacement by lanthanum in subcellular compartments of rat ventricular myocytes: characterisation by electron probe microanalysis.

OBJECTIVE: Much of the calcium in cardiac myocytes resides in a kinetic compartment defined by rapid exchange and rapid displacement by La3+. The aim of this study was to ascertain the subcellular location of this calcium pool. METHODS: Electron probe microanalysis (EPMA) was used to measure redistribution of total calcium in rat cardiac myocytes after 30 s in 1 mM lanthanum. "Cells", mitochondria, and myofibrils were separately analysed. The data permitted calculating a third (difference) compartment, containing primarily sarcoplasmic reticulum, sarcolemma, and T tubule lumen. Total calcium levels in junctional sarcoplasmic reticulum and T tubule lumen were also measured directly. RESULTS: Lanthanum decreased total "cell" calcium from 1.4 (SEM 0.3) to 0.5(0.4) mmol.kg-1 dry weight (p < 0.05); loss from the third (difference) compartment was primarily responsible. Simultaneously, junctional sarcoplasmic reticulum increased from 5.1(0.6) to 8.2(0.9) mmol.kg-1 dry weight (p < 0.05), while the T tubule lumen was unchanged. CONCLUSIONS: These results suggest that lanthanum displaced calcium primarily from sarcolemmal sites and that calcium redistributed to sarcoplasmic reticulum from an intracellular source.

P-REX1 creates a positive feedback loop to activate growth factor receptor, PI3K/AKT and MEK/ERK signaling in breast cancer.

Phosphatidylinositol 3-kinase (PI3K) promotes cancer cell survival, migration, growth and proliferation by generating phosphatidylinositol 3,4,5-trisphosphate (PIP3) in the inner leaflet of the plasma membrane. PIP3 recruits pleckstrin homology domain-containing proteins to the membrane to activate oncogenic signaling cascades. Anticancer therapeutics targeting the PI3K/AKT/mTOR (mammalian target of rapamycin) pathway are in clinical development. In a mass spectrometric screen to identify PIP3-regulated proteins in breast cancer cells, levels of the Rac activator PIP3-dependent Rac exchange factor-1 (P-REX1) increased in response to PI3K inhibition, and decreased upon loss of the PI3K antagonist phosphatase and tensin homolog (PTEN). P-REX1 mRNA and protein levels were positively correlated with ER expression, and inversely correlated with PI3K pathway activation in breast tumors as assessed by gene expression and phosphoproteomic analyses. P-REX1 increased activation of Rac1, PI3K/AKT and MEK/ERK signaling in a PTEN-independent manner, and promoted cell and tumor viability. Loss of P-REX1 or inhibition of Rac suppressed PI3K/AKT and MEK/ERK, and decreased viability. P-REX1 also promoted insulin-like growth factor-1 receptor activation, suggesting that P-REX1 provides positive feedback to activators upstream of PI3K. In support of a model where PIP3-driven P-REX1 promotes both PI3K/AKT and MEK/ERK signaling, high levels of P-REX1 mRNA (but not phospho-AKT or a transcriptomic signature of PI3K activation) were predictive of sensitivity to PI3K inhibitors among breast cancer cell lines. P-REX1 expression was highest in estrogen receptor-positive breast tumors compared with many other cancer subtypes, suggesting that neutralizing the P-REX1/Rac axis may provide a novel therapeutic approach to selectively abrogate oncogenic signaling in breast cancer cells.

Posttraumatic stress disorder after treatment for breast cancer: prevalence of diagnosis and use of the PTSD Checklist-Civilian Version (PCL-C) as a screening instrument.

The presence of a posttraumatic stress disorder (PTSD) diagnosis in women (n = 82) diagnosed with Stage 0-IIIA breast cancer was assessed 6 to 72 months after cancer therapy. The PTSD Checklist-Civilian Version (PCL-C) and the PTSD module for the Structured Clinical Interview for DSM-IV, Nonpatient Version, PTSD module (SCID-NP-PTSD) were administered in a telephone interview. SCID-NP-PTSD results indicated prevalence rates of 6% and 4% for current and lifetime PTSD, respectively. Use of the recommended cutoff score of 50 on the PCL-C to determine diagnosis of current cancer-related PTSD resulted in a sensitivity of .60 and a specificity of .99 with 2 false-negative diagnoses. In conclusion, PTSD can be precipitated by diagnosis and treatment of breast cancer, and the PCL-C can be a cost-effective screening tool for this disorder.

Clinical issues and treatment strategies in stress-oriented athletes.

Psychological stress disorders in athletes have become an increasingly important area of study within the last decade as a result of added interest in sports psychology. Scientific inquiry into the impact of life stress events on the health of athletes has only recently been the focus of clinical study. At the forefront of today's understanding of stressful events and its impact on the human organism are a variety of theories which argue either that: stress lies within the environmental input; that it is the cognitive appraisal; that it lies toward environmental input; or that it is a multivariant, multiprocess system that views no single variable or process as the aetiology or psychopathology in the organism. Within the framework of sports medicine, it is seen rather as a complex system of variables that address the environment, the personality of the athlete and the impact of stressful life events on both.

Sports medicine in the new millennium: a vision for 2020.

Globalisation, empowerment and technological change will determine the emerging directions in sports medicine in the new millennium. Networks and alliances of scientist and clinician services, as well as electronic profiling of athletes' learning styles, genetic predisposition and other variables, will enhance the spectrum of sports medicine services. Visionary direction will require changes in the organisational paradigms employed, the communication of information to athletes and coaches and the methodologies of assessment. An emphasis on prevention science and clinical and educational interventions will require a clearer focus. The sports medicine scientist and clinician of today must utilise the endowments suggested by Covey and the multiple intelligence models advanced by Gardner in capturing the clarity of focus for sports medicine in the new millennium.

Gambling as an addictive disorder among athletes: clinical issues in sports medicine.

This article examines the role of gambling as an addictive disorder experienced by athletes, both college and professional. Gambling may often be seen as a comorbid factor with other addictions and with depression among athletes. The focus on addictions among athletes has gained considerable attention among sports medicine clinicians. Diagnostic indicators, risk and protective factors, and a stage model of addiction among athletes are addressed. An algorithm and pathway of care for athletes with an addictive disorder is offered as are recommendations that sports physicians, sports medicine specialists, coaches and counsellors need to address athletes who have an addictive disorder.

Urinary metabolites of 3a,4,5,6,7,7a-hexahydro-3-(1-methyl-5-nitro-1H-imidazol-2-yl)-1,2-benzisoxazole in the dog.

The antiprotozoal drug 3a,4,5,6,7,7a-hexahydro-3-(1-methyl-5-nitro-1H-imidazol-2-yl)-1,2-benzisoxazole (I), which exhibits activity against trypanosomiasis, is also antibacterial in vivo. Since the urine from a dog dosed with I showed a broader spectrum of antibacterial activity than I itself, metabolites from this urine were isolated and partially characterized. The metabolites were mono- and dihydroxy-substituted species with the hydroxyl groups on carbons 4--7 of the hexahydrobenzisoxazole ring. These observations led to the synthesis of several such hydroxy derivatives of I, and their properties fully supported the proposed positions of metabolic hydroxylation. One synthetic compound, the 6,7-cis-dihydroxy compound, exhibited higher antibacterial activity against Salmonella schottmuelleri in mice and greater trypanocidal activity in vivo against Trypanosoma cruzi (Brazil strain) than I.

The lack of antifungal activity by avermectin B1a.

Streptomyces avermitilis produces avermectin, oligomycin and a polyene antifungal. The latter two compounds account for the antifungal activity in the methanol extracts of the fermentation broth. Pure avermectin does not inhibit fungi or affect fungal chitin metabolism.

Thienamycin, a new beta-lactam antibiotic. I. Discovery, taxonomy, isolation and physical properties.

A new beta-lactam antibiotic, named thienamycin, was discovered in culture broths of Streptomyces MA4297. The producing organism, subsequently determined to be a hitherto unrecognized species, is designated Streptomyces cattleya (NRRL 8057). The antibiotic was isolated by adsorption on Dowex 50, passage through Dowex 1, further chromatography on Dowex 50 and Bio-Gel P2, and final purification and desalting on XAD-2. Thienamycin is zwitterionic, has the elemental composition C11H16N2O4S (M.W. = 272.18) and possesses a distinctive UV absorption (lambda max = 297 nm, epsilon = 7,900). Its beta-lactam is unusually sensitive to hydrolysis above pH8 and to reaction with nucleophiles such as hydroxylamine, cysteine and, to a lesser degree, the primary amine of the antibiotic itself. The latter reaction results in accelerated inactivation at high antibiotic concentrations.

Family mediation: clinical strategies in mediating child custody.

Family medicine has only begun to explore the extent of its contribution to the process of family mediation--the clinical application of conflict resolution theory to the divorce process. This article reviews the literature on the impact of separation and divorce on families and recommends the use of family mediation as a clinical strategy to sensitize parents to the needs of the children during the divorcing process. Goals of family mediation include the assurance that the children have frequent and continuing contact with natural parents to the extent that this is to the benefit of the child. A specific model of family mediation is presented and the role of family physicians in the mediation is explored.

Aedes albopictus distribution, abundance, and colonization in Lee County, Florida, and its effect on Aedes aegypti.

In 1992 the known southern limit of Aedes albopictus in Florida was in Lee County. Through oviposition surveillance, the distribution of Ae. albopictus was determined, and its frequency relative to Aedes aegypti and colonization pattern of areas previously occupied by Ae. aegypti were examined in Lee County. The data collected in the first year of surveillance demonstrate the ability of Ae. albopictus to rapidly and preferentially colonize large expanses of rural southwest Florida. Urban and suburban areas of the county showed slower colonization rates. In suburban areas, Ae. albopictus became the dominant container-breeding mosquito species, whereas it did not become dominant in urban areas. During the study period, Ae. albopictus did not displace Ae. aegypti in urban or suburban habitats. The southern limit of Ae. albopictus moved a distance of 8.1 km (5 mi.) in 6 wk to the southern border of the county.

Temephos distribution and persistence in a southwest Florida salt marsh community.

The distribution and persistence of the mosquito larvicide temephos was monitored throughout an intertidal salt marsh community in southwest Florida following routine aerial applications of Abate 4-E (43% temephos) from 1988 through 1993. Temephos was found to be more highly concentrated in the surface water microlayer than in mid-depth water, exhibiting a mean of 330 micrograms/liter at the surface and 12 micrograms/liter at mid-depth from 1 fl. oz./acre applications and 120 micrograms/liter in the surface and 4.5 micrograms/liter in mid-depth water for 0.5 fl. oz./acre applications. Concentrations at both surface and mid-depth diminished rapidly within the first 24 hours. Mangrove leaves provided the most persistent reservoir for temephos, remaining more than 7 days. Temephos residues also were observed in select salt marsh organisms, including the sheepshead minnow (Cyprinodon variegatus), adult fiddler crabs (Uca rapax) and the ribbed mussel (Geukensia sp.).

Fate and toxicity of temephos applied to an intertidal mangrove community.

The distribution, persistence, and toxicity of the mosquito larvicide temephos was monitored following aerial applications to an intertidal mangrove community in Lee County, Florida. The amount of temephos penetrating to the mangrove floor ranged from 15 to 70% of the amount entering the upper leaf canopy, with 50-60% of that applied remaining on the mangrove leaves. Rainfall caused an additional influx of temephos from the leaves to the mangrove floor. Residues were detected in intertidal water at 2 h, but not 4 h after application. However, temephos was observed to persist in simulated tidal pools and on mangrove leaves for up to 72 h and in oysters for up to 48 h after application. Marine organisms placed in cages at 3 test sites and a control site were monitored for toxic effects. Mortality among natural mosquito larvae was simultaneously monitored. Mysids (Mysidopsis bahia) exhibited a significant mortality at one site during 1 of 3 applications monitored; however, no correlation was observed between mortality and temephos concentration in water. No significant mortality was observed for the other organisms, which included: brown shrimp (Panaeus aztecus), grass shrimp (Palaemonetes pugio), juvenile snook (Centropomis undecimalis) and sheepshead minnow (Cyprinodon variegatus).

Family violence: clinical indicators among military and post-military personnel.

Child and spouse abuse continues to be a critically important problem for the medical and mental health professions. Examined are recent clinical data and research addressing this most serious concern among military and post-military personnel. Criteria useful in the identification of risk persons and diagnosis and treatment of family violence are discussed. Specific attention is given to the diagnostic indicators, the abusing family profile, the traumatic process of abuse, and strategies relevant to psychiatric intervention. Guidelines for military mental health and medical professionals are explored.

Paternal absence and its effect on adolescent self-esteem.

Recent research has indicated that father absence is significantly related to self-concept of black adolescent males. Results suggest that where paternal absence exists in the home situation, the level of self-esteem tended to be affected more for males than for females. Where father was absent in the home, males tended also to have lower levels of self-esteem than females. Where self-esteem of the child and core-facilitative conditions in mother were correlated significantly (p less than .05), male self-esteem was likely to be affected negatively. Therefore, presence of maternal core-facilitative conditions can favourably effect self-esteem of both male and female adolescents in father-absent homes.

Assessment of life stress events: the etiology and measurement of traumatic stress disorder.

The impact of stressful life events on health has been of considerable interest from a cross-cultural perspective. Examined herein is the etiology and onset of post-traumatic stress disorder with careful review of the diagnostic criteria, current measures used and clinical dimensions of PTSD. Also examined from a cross-cultural perspective is how psychological trauma may be processed by victims of trauma and subsequent approaches both pharmacological and psychotherapeutic to the treatment of post-traumatic stress disorder.

The adult nonsurvivor of child abuse.

There is a growing clinical research interest in the long-term effects of victimization in childhood and the difficulty the victimized child may experience in adulthood. Examined are two case illustrations of individuals who were abused as children. The results of their dysfunctional childhood have yielded massive failures to cope and adjust to adult stress situations and have resulted in each case with the development of psychopathology that has impaired their adult lives. Issues and import for clinical practice and future research are discussed.