Relationship between the onset of oestrus, the preovulatory surge in luteinizing hormone and ovulation following oestrous synchronization and superovulation of farmed red deer (Cervus elaphus).

The timing of ovulation relative to the onset of oestrus and the preovulatory surge in luteinizing hormone (LH) was studied in red deer following treatments to synchronize oestrus and induce either a monovulatory or superovulatory response. Mature hinds (n = 36) were allocated randomly to two mating groups (n = 16 + 20), with respective treatments staggered by 4 weeks during the 1990 rut (March-April). Each hind was treated with an intravaginal controlled internal drug releasing (CIDR)-type S device for 14 days. Treatments to induce a monovulatory response included CIDR device alone (treatment A; n = 4 + 8) and additional injection of 200 iu pregnant mares' serum gonadotrophin (PMSG) at device removal (treatment B; n = 4 + 4). Treatments to induce a superovulatory response included injections of 200 iu PMSG and 0.5 units ovine follicle-stimulating hormone (FSH) at about time of removal of CIDR devices (treatment C; n = 4 + 4) and further treatment with gonadotrophin-releasing hormone (GnRH) analogue 18 h after removal of CIDR devices (treatment D; n = 4 + 4). The hinds were run with crayon-harnessed stags from insertion of CIDR devices (12 March or 9 April) and blood samples were taken every second day to determine plasma progesterone. Further blood samples were collected for determination of plasma LH and progesterone via indwelling jugular cannulae every 2 h for 72 h from removal of CIDR devices. Hinds were allocated randomly to an initial ovarian examination by laparoscopy at either 16 or 20 h (A and B), or 12 or 16 h (C and D) after the onset of oestrus, with laparoscopy repeated at intervals of 8 h until either ovulation was recorded (A and B), or for four successive occasions (C and D). All hinds received cloprostenol injections 15 days after device removal. A total of 28 hinds (78%) exhibited oestrus and a preovulatory LH surge, with mean (+/- SEM) times to onset of oestrus of 44.6 +/- 1.0 h (A; n = 7), 37.4 +/- 2.0 h (B; n = 7), 16.3 +/- 1.7 h (C; n = 6) or 14.0 +/- 1.7 h (D; n = 8). Failure to exhibit oestrus or LH surge was most prevalent among hinds in treatment A early in the rut.(ABSTRACT TRUNCATED AT 400 WORDS)     

Production and regulation of cellulase by two strains of the rumen anaerobic fungus Neocallimastix frontalis.

Cellulase production was examined in two strains of Neocallimastix frontalis, namely, PN-1 isolated from the ovine rumen, and PN-2 from the bovine rumen. For both strains, carboxymethylcellulase (CMCase) had a pH optimum of 6.0 and a temperature optimum of 50 degrees C. CMCase resided mainly in the culture fluid, and activities up to 170 U ml-1 (1 U represents 1 microgram of glucose equivalents released per min) were obtained for cultures grown on 2.5 mg of cellulose ml-1. For resting cultures of strain PN-1, the yield of CMCase increased from 9.9 X 10(3) to 10.4 X 10(4) U per g of cellulose degraded, as the initial cellulose concentration decreased from 10 to 0.58 mg ml-1. The range for PN-2 was 8.1 X 10(3) to 11 X 10(4) U g-1. Shaking cultures improved yields for strain PN-1 but not for PN-2. Decreased CMCase production at high initial cellulose concentrations concurred with accumulation of glucose, and addition of glucose (4 mg ml-1) to cultures grown on low cellulose in which none of the sugar accumulated repressed CMCase. Adsorption of CMCase was excluded as a likely explanation for decreased yields at high initial cellulose as only a low proportion (less than 20%) of the enzyme was adsorbed onto the growth substrate. Exoglucanase, measured with alkali-treated Sigmacell or Avicel, gave low levels of activity in the culture fluid (less than 2 U ml-1) and did not appear to be associated with the fungal rhizoid, as treatment with various solubilizing agents failed to give increased activity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evolutionary Implications of Dental Eruption in Dasypus (Xenarthra)

Late eruption of the permanent dentition was recently proposed as a shared anatomical feature of endemic African mammals (Afrotheria), with anecdotal reports indicating that it is also present in dasypodids (armadillos). In order to clarify this question, and address the possiblity that late eruption is shared by afrotherians and dasypodids, we quantified the eruption of permanent teeth in Dasypus, focusing on growth series of D. hybridus and D. novemcinctus. This genus is the only known xenarthran that retains two functional generations of teeth. Its adult dentition typically consists of eight upper and eight lower ever-growing (or euhypsodont) molariforms, with no premaxillary teeth. All but the posterior-most tooth are replaced, consistent with the identification of a single molar locus in each series. Comparison of dental replacement and skull metrics reveals that most specimens reach adult size with none or few erupted permanent teeth. This pattern of growth occurring prior to the full eruption of the dentition is similar to that observed in most afrotherians. The condition observed in Dasypus and many afrotherians differs from that of most other mammals, in which the permanent dentition erupts during (not after) growth, and is complete at or near the attainment of sexual maturity and adult body size. The suture closure sequence of basicranial and postcranial epiphyses does not correlate well with dental eruption. The basal phylogenetic position of the taxon within dasypodids suggests that diphyodonty and late dental replacement represent the condition of early xenarthrans. Additionally, the inferred reduction in the number of molars to a single locus and the multiplication of premolars represent rare features for any living mammal, but may represent apomorphic characters for Dasypus.     

Hyphal walls of isolated lichen fungi

The hyphal walls of three mycobionts, isolated from the lichens Xanthoria parietina, Tornabenia intricata and Sarcogyne sp. were investigated by two techniques: microautoradiography of fungal colonies exposed to radioactive carbohydrate precursors; and binding, in vivo, of fluorescein conjugated lectins to hyphal walls of such colonies.N-[³H] acetylglucosamine was readily incorporated into tips, young hyphal walls and septa of the three mycobionts and the free-living fungus Trichoderma viride, but not into Phytophthora citrophthora, indicating that chitin is a major component of the mycobionts' hyphal walls. All three mycobionts, but neither of the free-living fungi, incorporated [³H] mannose and [³H] mannitol into their hyphal walls.Fluorescein-conjugated wheat germ agglutinin was bound to the hyphal walls of the three mycobionts and T. viride, but not to the walls of P. citrophthora; the binding pattern was similar to the grain pattern obtained in autoradiographs after short N-[³H] acetylglucosamine labelling. As wheat germ agglutinin binds specifically to chitin oligomers, the lectin binding tests further confirmed that chitin is a mycobiont hyphal wall component.Binding characteristics of several fluorescein-conjugated lectins to the three mycobionts indicated that this technique can yield useful information concerning the chemical composition of hyphal wall surfaces.List of abbreviations FITC fluorescein isothiocyanate - WGA wheat germ agglutinin - TCA trichloroacetic acid - PNA peanut agglutinin - LA lotus agglutinin - Glc NAc N-acetylglucosamine - ConA concanavalin A - SBA soybean agglutinin - WBA waxbean agglutinin Part of an M.Sc. thesis submitted by A. Braun to the Department of Botany, Tel Aviv University.     

Enhanced Connexin-43 and α-Sarcomeric Actin Expression in Cultured Heart Myocytes Exposed to Triiodo-l-thyronine

This study examined whether triiodo-L-thyronine (T3) affects the expression of the major intercellular channel protein, connexin-43, and contractile protein alpha-sarcomeric actin. Cultured cardiomyocytes from newborn rats were treated on day three in culture with 10 or 100 nM T3 and examined 48 and 72 h thereafter. Treated and untreated cells were examined by immunofluorescence and electron microscopy. Expression levels of Cx43 and sarcomeric alpha-actin were monitored by Western blot analysis. Immunofluorescence labeling showed cell membrane location of Cx43 in punctuate gap junctions, whereby fluorescence signal area was significantly higher in cultured cardiomyocytes exposed to T3. This correlated with electron microscopical findings showing increased numbers and size of gap junction profiles, as well as with a significant dose-dependent increase of Cx43 expression detected by Western blot. Immunofluorescence of sarcomeric a-actin was enhanced and its expression increased dose- and time-dependently in T3-treated cultured heart myocytes. However, exposure to the higher dosage (100 nM) of T3 caused mild disintegration of sarcomeric a-actin in some myocytes, suggesting an over-dosage. The results indicate that T3 up-regulates Cx43 and accelerates gap junction formation in cultured neonatal cardiomyocytes. They suggest that thyroid status cannot only modulate the mechanical function of cardiomyocytes but also cell-to-cell communication essential for myocardial electrical and metabolic synchronizations.     

Dental Ontogeny in Macroscelides proboscideus (Afrotheria) and Erinaceus europaeus (Lipotyphla)

We investigated the state of dental eruption in specimens of Macroscelides proboscideus and Erinaceus europaeus of known age. When M. proboscideus reaches adult size and sexual maturity, few or none of its replaced permanent cheek teeth have erupted. The approximate sequence of upper tooth eruption is P1, [I3, C, M1], [I1–2], M2, P4, [P2, P3]. Chronologically, E. europaeus erupts its molars and most premolars prior to M. proboscideus; but its first two upper incisors erupt after those of M. proboscideus, and its canines erupt around the same time. The approximate sequence of upper tooth eruption in E. europaeus is [M1, M2, P2, I3], C, M3, P4, P3, I2, I1. Unlike M. proboscideus, E. europaeus does not reach adult size until all permanent teeth except for the anterior incisors have erupted. While not unique among mammals, the attainment of adult body size prior to complete eruption of the permanent cheek teeth is particularly common among macroscelidids and other afrotherians.     

Defensive medicine in Israel - a nationwide survey

Background

Defensive medicine is the practice of diagnostic or therapeutic measures conducted primarily as a safeguard against possible malpractice liability. We studied the extent, reasons, and characteristics of defensive medicine in the Israeli health care system.

Methods and Findings

Cross-sectional study performed in the Israeli health care system between April and July 2008 in a sample (7%) of board certified physicians from eight medical disciplines (internal medicine, pediatrics, general surgery, family medicine, obstetrics and gynecology, orthopedic surgery, cardiology, and neurosurgery). A total of 889 physicians (7% of all Israeli board certified specialists) completed the survey. The majority [60%, (95%CI 0·57–0·63)] reported practicing defensive medicine; 40% (95%CI 0·37–0·43) consider every patient as a potential threat for a medical lawsuit; 25% (95%CI 0·22–0·28) have previously been sued at least once during their career. Independent predictors for practicing defensive medicine were surgical specialty [OR = 1.6 (95%CI 1·2–2·2), p = 0·0004], not performing a fellowship abroad [OR = 1·5 (95%CI 1·1–2), p = 0·027], and previous exposure to lawsuits [OR = 2·4 (95%CI 1·7–3·4), p<0·0001]. Independent predictors for the risk of being sued during a physician''s career were male gender [OR = 1·6 (95%CI 1·1–2·2), p = 0·012] and surgery specialty [OR = 3·2 (95%CI 2·4–4·3), p<0·0001] (general surgery, obstetrics and gynecology, orthopedic surgery, and neurosurgery).

Conclusions

Defensive medicine is very prevalent in daily physician practice in all medical disciplines. It exposes patients to complications due to unnecessary tests and procedures, affects quality of care and costs, and undermines doctor-patient relationships. Further studies are needed to understand how to minimize defensive medicine resulting from an increased malpractice liability market.