Delayed density-dependence in a small-rodent population

The role of delayed density-dependent processes in the dynamics of animal populations poses a problem for ecologists; although generally assumed important in populations that show cyclic or chaotic fluctuations, little experimental evidence for such processes exist. Through manipulation of vole densities within enclosed areas it was shown that reproduction, recruitment, and body growth rate in introduced populations were negatively affected by high previous density. In addition, female movement patterns shifted, and territoriality as well as home-range size was increased after high density. The observed changes in female spacing-behaviour suggested that negative effects of previous density were partly mediated by social interactions, and agreed with the finding that smaller (less competitive) females were the ones suffering most from increased competition. Contrary to expectations from recent work, predation could be excluded as the cause of delayed density-dependence in this study. Instead, chemical analyses of a dominating food plant suggested that herbivory at high vole-density had delayed negative effects on food quality.

Preovulatory sonographic uterine receptivity index (SURI): usefulness as an indicator of pregnancy in women undergoing assisted reproductive treatments

To evaluate the uterine component as a determinant variable in the probability of establishing a pregnancy after assisted reproductive treatments, we introduced a mathematical formula derived from standard endovaginal uterine monitored color Doppler imaging parameters. We analyzed 102 cycles of ovarian stimulation with leuprolide acetate and exogenous gonadotropins resulting in 52 clinical pregnancies by stepwise logistic regression analysis. Sonographic endometrial pattern, thickness, diastolic blood flow, and resistive index variables were transformed into categorical variables and forced to yield a regression equation. Sonographic uterine receptivity index was calculated as a summation of four times endometrial pattern, five times resistive index, and two times diastolic blood flow. This index yielded values for each patient in a range of 0 to 15. Scores > or = 13 were associated with a successful outcome in 79.4% of the patients, whereas scores between 8 and 12 were accompanied by 45.8% pregnancy rates (P = 0.01), and scores < or = 7 had successful treatment outcome in only 7.7% (P = 0.0001). The scores obtained by this mathematical equation provide the ability to make reliable predictions about the outcome of assisted reproductive treatments in women undergoing ovulation induction with leuprolide acetate and human menopausal gonadotropins.

Effects of pravastatin with niacin or magnesium on lipid levels and postprandial lipemia

This study was designed to evaluate the therapeutic effectiveness of 3 different pharmacologic lipid-lowering regimens in the treatment of patients with clustered lipid risk factors. Sixty-five patients with low high-density lipoprotein (HDL) levels and hypertriglyceridemia were randomized to 1 of 3 treatment arms: pravastatin/niacin, pravastatin/magnesium, or pravastatin/placebo. After 18 weeks, patients in the pravastatin/niacin group had a -41% change in the total cholesterol/HDL ratio compared with -13% in the pravastatin/magnesium arm and -16% in the pravastatin/placebo group. The HDL2 and HDL3 subfractions, as well as the apolipoprotein A-I levels, were increased significantly only in the pravastatin/niacin arm. The levels of small dense low-density lipoprotein (LDL) cholesterol (LDL3) were decreased to a greater extent in the pravastatin/niacin arm (-43%) than in either the pravastatin/magnesium (-13%) or the pravastatin/placebo (-20%) arm. Only the pravastatin/niacin regimen significantly diminished postprandial lipemia (-32% change in the remnant particle triglyceride concentration and decreased very-low-density lipoprotein remnant levels). Thus, in this group of patients with clustered risk factors, the combination of pravastatin and niacin resulted in significant improvements in HDL and triglyceride levels, total cholesterol to HDL ratio, small dense LDL levels, and postprandial lipemia. Pravastatin alone or in combination with magnesium resulted in less significant changes that were largely limited to LDL cholesterol reduction.

Murine epidermal growth factor (EGF) fragment (33-42) inhibits both EGF- and laminin-dependent endothelial cell motility and angiogenesis

Laminin, murine epidermal growth factor (mEGF), and the synthetic laminin peptide Lam.B1(925-933) (a linear peptide from the B1 chain of murine laminin, CDPGY1GSR-amide) all stimulate endothelial cell motility above basal rates, whereas a synthetic mEGF fragment, mEGF33-42 (a linear peptide from the C-loop of mEGF, acetyl-C-[S-Acm]-VIGYSGDR-C-[S-Acm]-amide), inhibits motility. In both human SK HEP-1 and embryonic chick endothelial cells, mEGF33-42 blocks both EGF- and laminin-stimulated locomotion of endothelial cells. In vivo, mEGF33-42 also blocks both laminin- and mEGF-induced angiogenesis in the chick. In the human cell line. Lam.B1(925-933) has an additive effect in coincubation with either laminin or mEGF, but it blocks their effects in the chick cells. Lam.B1(925-933) alone stimulates angiogenesis in the chick but blocks laminin-induced angiogenesis. Thus, mEGF33-42 acts as a general laminin antagonist, whereas Lam.B1(925-933) acts as a laminin agonist in human cells, but in chick cells it acts as a partial antagonist. We propose that the presence of an anionic group at the eighth residue of mEGF33-42 may be the source of the antagonistic effects seen with this peptide as compared with the laminin fragment. These findings have important implications in the design of human antiangiogenic agents, and also in the use of chick models in the study of human disease.

Prospective study of adenovirus antigen detection in eye swabs by radioimmune dot-blot

Rapid laboratory diagnosis of ocular adenovirus infection is crucial in the containment of nosocomial transmission of the virus. In a large prospective study of adenovirus assay in eye swabs, antigen detection by radioimmune dot-blot (turnaround time 72 hours) achieved a sensitivity of 67% (239/355) and a specificity of 93% (3065/3285) in comparison with virus culture (median turnaround time 14 days). When specimens weakly reactive for adenovirus antigen, or equally reactive for both adenovirus antigen and Chlamydia trachomatis antigen, were considered falsely reactive in the adenovirus test, the sensitivity of the latter was reduced and false positive reactions were only marginally less frequent. The radioimmune dot-blot provides a more rapid diagnosis of ocular adenovirus infection than virus culture, but the high risk of false negative and in particular false positive results limits its clinical utility.

Small patella syndrome

We report on 2 sporadic cases of small patella syndrome (coxo-podo-patellaire syndrome) most probably representing new mutations. Both children showed retarded patellar bone age (small patellae in Patient 1 and absent patellae in Patient 2) and pelvic abnormalities. Patient 1 who was fully investigated had an unusual facies with characteristic morphological abnormalities of the forefoot and generalized bone changes. Patient 2 was not available for examination and only X-ray films of his knees, pelvis, and chest were available. These were all abnormal. He was said to have an "unusual facies" with flattened nose and prominent forehead but no further information was available. We think that small patella syndrome (coxo-podo-patellaire syndrome) is a generalized bone dysplasia with morphological and diagnostic radiographic appearances.

Value of screening for oro-pharyngeal Chlamydia trachomatis infection

AIMS

To determine whether oro-pharyngeal colonisation by Chlamydia trachomatis occurs in patients at risk of genital chlamydia infection; to determine whether screening pharyngeal specimens by polymerase chain reaction (PCR) increases detection of C trachomatis compared with isolation and the immune dot blot test; and to correlate the detection of C trachomatis and Neisseria gonorrhoeae in the pharynx with a history of oro-genital contact.

METHODS

Thirteen homosexuals and 11 heterosexuals were included in the study. Urogenital and pharyngeal specimens were tested for C trachomatis and N gonorrhoeae using standard clinical diagnostic procedures. Two different PCR methodologies were also used to detect C trachomatis in the pharyngeal specimens. Results were correlated with the mode of sexual practice.

RESULTS

Oro-genital sexual contact was practised by 64.9% (72/111) of heterosexuals in addition to penetrative penovaginal intercourse. Additionally, 62.1% (77/124) of all patients did not use any form of barrier protection. Of those who admitted to oro-genital sexual contact, 17.6% of patients with a genital chlamydial infection and 36.4% of those with genital gonorrhoea also had asymptomatic pharyngeal colonisation. C trachomatis was detected in three of 124 (2.4%) pharyngeal specimens by PCR which were reported as negative by chlamydial culture; one was positive by the immune dot blot test.

CONCLUSION

The majority of patients practised unprotected oro-genital contact and significant pharyngeal colonisation by C trachomatis and N gonorrhoeae occurred if genital infection was present. Despite the use of PCR in a population at high risk of sexually transmitted disease, the prevalence of chlamydia in the pharynx was very low. This indicates that transmission of C trachomatis to the oro-pharynx does not pose a serious health risk and that screening of patients for oro-pharyngeal C trachomatis is not worthwhile.

Investigations using a novel monoclonal antibody to the glycosylphosphatidylinositol-anchored protein that carries Gregory, Holley, and Dombrock blood group antigens

BACKGROUND

The high-frequency Hy and Gya antigens have been shown to reside on the same protein. Gy(a-) Hy-negative red cells are also Do(a-b-). A mouse monoclonal antibody, 5B10, was produced with specificity related to the human Gregory, Holley, and Dombrock blood group antigens.

STUDY DESIGN AND METHODS

The antibody reacted in direct hemagglutination assays, and its specificity was investigated by radioimmunoassay, inhibition assay, and Western blotting.

RESULTS

The 5B10 antibody failed to bind to abnormal paroxysmal nocturnal hemoglobinuria red cells and human erythroleukemia cell line K562, but it was weakly reactive with HEL cells. Red cells, but not other circulating hematopoietic cells, express the 5B10 antigen. The 5B10 antibody had a specificity similar but not identical to that of Gya. Gy(a-) Hy-negative red cells reacted extremely weakly with 5B10 antibody, but Gy(a-) Hy-negative red cells treated with a variety of proteases bound 5B10 antibody strongly. This suggests that these cells express a variant form of the protein recognized by 5B10.

CONCLUSION

Identification of a monoclonal antibody to this glycosylphosphatidylinositol-linked protein opens a new avenue for investigation of the biochemistry, genetics, and function of the glycosylphosphatidylinositol-linked protein that bears the Gya, Hy, and Do antigens.

The influence of environmental factors in incidents of disruptive behavior

1. Disruptive behavior is an annoying and potentially dangerous problem in most nursing homes. Disruptive behaviors can be both physical and verbal. 2. Changes associated with termination of disruptive behaviors included the reduction of external environmental stimuli, reduction of perceived threats to the patient's personal freedom and fulfillment of basic physical needs, fulfillment of needs for interpersonal support, a simple request to the disruptive person that the behavior be discontinued, provision for increased freedom by releasing the person from a gerichair or wheelchair with rollbar, separation of residents involved in disputes, and resolution of disputes over belongings. 3. In order to initiate changes that will reduce the frequency of such behavior or mitigate its harmful effects, nurses must have a better understanding of how environmental factors influence the evolution of disruptive episodes and plan appropriate and specific nursing interventions.

Selective salpingography with an insemination catheter in the treatment of women with cornual fallopian tube obstruction

The effectiveness of selective tubal cannulation using a simple and inexpensive tubal insemination catheter was evaluated in 23 infertile patients with cornual obstruction demonstrated by hysterosalpingography. Selective fluoroscopic tubal catheterization was accomplished in 95% of the patients with resulting tubal patency in 70% of the procedures (28 recanalizations out of 40 Fallopian tubes). Eight patients (34.8%, eight out of 23) became pregnant, six went on to full-term deliveries and two experienced spontaneous first-trimester abortions. One women conceived twice, and delivered a singleton pregnancy after the first recanalization and a twin gestation after the second salpingography. No complications were reported. The results of this study emphasize the ease, cost effectiveness and safety of this method, encouraging its use in patients with cornual Fallopian tube obstruction either as the sole therapeutic approach or in association with other assisted conception treatment alternatives.

Engineered serine protease inhibitor prevents furin-catalyzed activation of the fusion glycoprotein and production of infectious measles virus

We have identified the major cellular endoprotease that activates the fusion (F) glycoprotein of measles virus (MV) and have engineered a serine protease inhibitor (serpin) to target the endoprotease and inhibit the production of infectious MV. The F-protein precursor of MV was not cleaved efficiently into the mature F protein in human colon carcinoma cells lacking functional furin, indicating that furin is the major enzyme responsible for activation of the MV F protein. A human serpin alpha 1-antitrypsin variant was engineered to specifically inhibit furin. When expressed from a recombinant vaccinia virus in primate cells infected by MV, the engineered serpin (alpha 1-PDX) specifically inhibited furin-catalyzed cleavage of the F-protein precursor without affecting synthesis of other MV proteins. We generated human glioma cells stably expressing alpha 1-PDX. MV infection in these cells did not result in syncytia. The infected cells produced all the MV proteins, but the F-protein precursor remained largely uncleaved. This did not prevent virus assembly. However, the released virions contained inactive F-protein precursor rather than mature F protein, and infectious-virus titers were reduced by 3 to 4 orders of magnitude. These results show that a mature F protein is not required for the assembly of MV but is crucial for virus infectivity. The engineered serpin may offer a novel molecular antiviral approach against MV.

Peripheral blood stem cell transplants for multiple myeloma: identification of favorable variables for rapid engraftment in 225 patients

Transfusion of autologous peripheral blood stem cells (PBSCs) of good quality ensures fast hematopoietic engraftment after myeloablative therapy with a decrease in procedure-related morbidity and mortality. We have analyzed variables influencing the kinetics of engraftment, and therefore reflecting the quality of PBSC collections, in 225 patients with newly diagnosed or refractory multiple myeloma (MM) who received an autotransplant in support of high dose melphalan (200 mg/m2); 132 of these patients also completed a second transplant. All PBSCs were collected before the first transplant after high-dose cyclophosphamide (6 g/m2) and hematopoietic growth factors, mainly granulocyte-macrophage colony-stimulating factor. PBSCs were administered either alone (91 patients) or with bone marrow (134 patients). A highly significant correlation was observed between the number of CD34+ cells per kilogram infused and prompt recovery of both granulocytes (P = .0001) and platelets (P = .0001). After correction for the proportion of patients with > or = 2 x 10(6)/kg CD34 PBSCs infused and with < or = 12 months of prior therapy, no difference in engraftment kinetics was seen between patients receiving PBSCs only and those also receiving bone marrow. Exposure to chemotherapy, even to < or = 6 months of alkylating agents, significantly delayed hematopoietic recovery posttransplantation. The threshold dose of CD34 cells necessary for prompt engraftment was > or = 2.0 x 10(6)/kg for patients with < or = 24 months of chemotherapy before the first transplant, whereas greater than 5 x 10(6)/kg CD34 cells were required to assure rapid recovery also in those with longer exposure. Such quantities, easily collected in the large majority of patients with shorter exposure (91%), were obtained in only 28% of patients with more than 24 months of prior chemotherapy. Rapid platelet recovery within a narrow range of time (before day 14) was almost invariably seen (94%) when greater than 5 x 10(6)/kg CD34 cells were infused, irrespective of the duration of prior therapy, whereas the range widened progressively when less CD34 cells were infused. In the absence of CD34 measurements, fast recovery of platelets to greater than 50 x 10(9)/L within 14 days after high-dose cyclophosphamide and < or = 12 months of prior chemotherapy were the best predictors of early engraftment. Prudent use of stem cell-damaging agents, such as melphalan and nitrosoureas, is recommended in MM patients who might be candidates for autotransplantation. Alternatively, PBSCs should be collected early after diagnosis.

Characterization of the mouse lymphotoxin-beta gene

Lymphotoxin-beta (LT-beta) is a member of the TNF family of ligands which when expressed with lymphotoxin-alpha (LT-alpha, i.e., the original LT or TNF-beta) forms a heteromeric complex with LT-alpha on the cell surface. The mouse gene structure was determined by both cDNA cloning and analysis of a genomic DNA fragment encompassing the TNF/LT locus in the H-2 region of chromosome 17. The mouse and human genomic structures were found to be similar in terms of location in the class III region of the MHC; however, the mouse gene lacks one intron found in most members of the family. Both the cDNA and the genomic sequences revealed an altered splice donor in the conventional intron 2 position, rendering it nonfunctional. The altered gene retains an open reading frame such that an additional 66 amino acids are inserted into the stalk region connecting the transmembrane domain with the receptor binding domain encoded by exon 4 in this type II membrane protein. Northern analysis showed that this gene is expressed predominantly in lymphoid organs. The outlining of the complete mouse TNF locus will further studies of the relationship between these genes and immune function.

Characterization of the mouse lymphotoxin-beta gene

Lymphotoxin-beta (LT-beta) is a member of the TNF family of ligands which when expressed with lymphotoxin-alpha (LT-alpha, i.e., the original LT or TNF-beta) forms a heteromeric complex with LT-alpha on the cell surface. The mouse gene structure was determined by both cDNA cloning and analysis of a genomic DNA fragment encompassing the TNF/LT locus in the H-2 region of chromosome 17. The mouse and human genomic structures were found to be similar in terms of location in the class III region of the MHC; however, the mouse gene lacks one intron found in most members of the family. Both the cDNA and the genomic sequences revealed an altered splice donor in the conventional intron 2 position, rendering it nonfunctional. The altered gene retains an open reading frame such that an additional 66 amino acids are inserted into the stalk region connecting the transmembrane domain with the receptor binding domain encoded by exon 4 in this type II membrane protein. Northern analysis showed that this gene is expressed predominantly in lymphoid organs. The outlining of the complete mouse TNF locus will further studies of the relationship between these genes and immune function.

Carboxyfluorescein and biotin neuromedin C analogues: synthesis and applications

Two neuromedin C (NC) analogues were constructed by Fmoc synthesis and in situ coupling of 4(5)-carboxyfluorescein or biotin to the N-terminus. Both displayed full agonism in an amylase release assay and cross-reacted fully with a NC-specific antiserum. Biotin NC functioned in a streptavidin-capture ELISA. Carboxyfluorescein NC was used to probe receptor localization in rat stomach. Specific NC binding sites, which did not interact with substance P, angiotensin I, or neurokinin A, were labeled in the antrum. Identity of NC binding sites was confirmed by microautoradiography. The specifically labeled cells were all found in the lamina propria and at least some of cells were identified as eosinophils.

Factor VIII gene inversions in severe hemophilia A patients

The mutations causing hemophilia A are very heterogeneous with the exception of a large inversion involving intron 22 in the factor VIII (FVIII) gene which appears to be the underlying defect in approximately 45% of all severely affected patients (FVIII < or = 1%). In these patients it is thought that the factor VIII gene is disrupted within intron 22 due to inappropriate recombination of FVIIIA with one of 2 homologous regions upstream of the factor VIII gene resulting in a large (approximately 500 kb) inversion. The inversion can be detected by Southern blot analysis and greatly enhances the accuracy of genetic counselling services available to families with severe hemophilia A. We report here the presence of this mutation in a study of 27 unrelated families with severe hemophilia. The factor VIII inversion was identified in 12 of 27 (44%) severe hemophilia A patients and has been successfully used for direct carrier analysis and prenatal diagnosis.

Secondary structure of the 33 kDa, extrinsic protein of Photosystem II: a far-UV circular dichroism study

The 33 kDa extrinsic protein of Photosystem II is an important component of the oxygen-evolving apparatus which functions to stabilize the manganese cluster at physiological chloride concentrations and to lower the calcium requirement for oxygen evolution. Chou-Fasman analysis of the amino-acid sequence of this protein suggests that this component contains a high proportion of alpha-helical structure and only relatively small amounts of beta-sheet structure. A computational study using more sophisticated techniques (Beauregard, M. (1992) Environ. Exp. Bot. 32, 411-429) concluded that the protein contained little periodically ordered secondary structure. In this study, we have directly measured the relative proportions of secondary structure present in the 33 kDa protein using far-ultraviolet circular dichroism spectroscopy. Our results indicate that, in solution, this protein contains a large proportion of beta-sheet structure (38%) and relatively small amounts of alpha-helical structure (9%). A structural model of the 33 kDa protein based on a constrained Chou-Fasman analysis (Teeter, M.M. and Whitlow, M (1988) Proteins 4, 262-273) is presented.