Inhibition of IgA1 proteinases from Neisseria gonorrhoeae and Hemophilus influenzae by peptide prolyl boronic acids

The alpha-aminoboronic acid analog of proline has been synthesized and incorporated into a number of peptides as the COOH-terminal residue. These peptide prolyl boronic acids are potent inhibitors of both the type 1 and type 2 IgA proteinases from Neisseria gonorrhoeae and Hemophilus influenzae, but not of the functionally similar IgA proteinase from Streptococcus sanguis. The best inhibitors synthesized thus far have Ki values in the nanomolar range (4.0 to 60 nM). These results indicate that the N. gonorrhoeae and the H. influenzae enzymes belong to the serine protease family of proteolytic enzymes while that from S. sanguis does not. As a group, the IgA proteinases have been noted for their remarkable specificity; thus, the peptide prolyl boronic acids reported here are the first small synthetic molecules to exhibit a relatively high affinity for the active site of an IgA proteinase and are therefore the first to yield some insight into the active site structure and specificity requirements of these enzymes.

Changing water-use patterns in a water-poor area: lessons for a trachoma intervention project

An epidemiological survey carried out in the Dodoma region of Tanzania found that high rates of trachoma infection in pre-school children were associated with unwashed faces. Prior to a planned trachoma intervention project, a pilot study was done on household decisions about water use and perceptions about face washing and eye disease. The study found that mothers overestimated the amount of water necessary to wash a child's face. In addition, mothers would not change their water-use priorities without the consent of their husbands and the support of the community. Therefore a health education program was designed to address the perception that face washing required a great deal of water. The program also sought to involve and re-educate the whole community rather than focus only on the mothers who were most likely to wash the children's faces.

Hygiene factors and increased risk of trachoma in central Tanzania

Trachoma remains the major infectious cause of blindness in many developing areas, especially where hygiene is poor. The practices and behaviors associated with an increased risk of trachoma were studied in central Tanzania, where a stratified random cluster sample of 8409 people was examined. Data were collected on family and individual characteristics and behaviors and on trachoma status. Overall, 60% of the children aged 1 to 7 years had active inflammatory trachoma, and 10% of those aged 60 years or older had trichiasis. Regression analysis showed that active inflammatory trachoma in children was associated with the characteristics of the more traditional families and several measures of poor personal hygiene. Two important risk factors for severe inflammatory trachoma were poor facial cleanliness in children (odds ratio of 1.7 [1.17, 2.50]) and household fly density (odds ratio of 1.63 [1.17, 2.29]). Both factors are potentially amenable to intervention. These data suggest that an intervention strategy aimed at these hygiene measures would provide an effective method of controlling trachoma in this region, and a similar approach may be useful in other areas.

Tetrapeptide inhibitors of the IgA1 proteinases from type I Neisseria gonorrhoeae

The six series of unique tetrapeptides and their blocked N-acetyl, C-amide, and N-acetyl-C-amide analogues which comprise the hinge region of human IgA1 (Ser224 to Ser240) have been synthesized and tested as inhibitors of the type 1 IgA1 proteinase elaborated by Neisseria gonorrhoeae (EC 3.4.24.13). Most series had at least one member with an IC50 value less than 1 mM. The most effective inhibitors came from the series Ser-Thr-Pro-Pro (P4-P1) and Pro-Thr-Pro-Ser (P1-P3'). One member from each series had an IC50 value in the low microM range. Magnetic resonance studies (Siemion, I. Z.; et al. Biophys. Chem. 1988, 31, 35) indicate that the various tetrapeptide series appear to have different preferred solution conformations. However, these do not appear to be correlated with affinity for the neisserial proteinase. The most effective inhibitors tend to have a threonine residue adjacent to the N-terminus and the P1 or P1' residues at either the N- or the C-terminus. These relationships are not exclusive however, as other inhibitors, which do not meet these criteria, bind reasonably well. The most effective substrate analogues outlined here are about one-half the size and bind to the neisserial proteinase 2 orders of magnitude more tightly than previously reported inhibitors.

Escalating doses of etoposide with cyclophosphamide and fractionated total body irradiation or busulfan as conditioning for bone marrow transplantation

In a phase I study 28 patients with lymphohematopoietic malignancies were treated with escalating doses of etoposide combined with cyclophosphamide 120 mg/kg and either fractionated total body irradiation (TBI) 1320 cGy in 11 fractions (n = 17) or busulfan 16 mg/kg (n = 11). Twenty transplants were allogeneic, seven autologous and one syngeneic. The maximally tolerated dose of etoposide in combination with TBI and cyclophosphamide was 60 mg/kg; at etoposide doses of 65 mg/kg three patients developed life-threatening or fatal mucosal toxicity. In combination with busulfan, the maximally tolerated dose of etoposide was 30 mg/kg. At an etoposide dose of 40 mg/kg two patients developed life-threatening or fatal toxicity (one mucosal, one hepatic). Mucositis requiring narcotic analgesics, hepatotoxicity, hematologic toxicity and interstitial pneumonitis were otherwise similar in TBI and busulfan-treated patients. Skin toxicity was observed significantly more often in the busulfan group. Five deaths occurred before day +30, two in the TBI group and three in the busulfan group. Eleven patients are surviving, ten in continuous complete remission, at a median of 9 (range 3-23) months following transplantation. Etoposide in combination with TBI and cyclophosphamide or busulfan and cyclophosphamide is associated with significant but acceptable toxicities. The maximally tolerated dose of etoposide is higher when combined with TBI than with busulfan. Promising response rates in this high risk group of hematologic malignancies warrant further evaluation of these etoposide containing conditioning regimens.

Injury and cost comparison of restrained and unrestrained motor vehicle crash victims

The use of active motor vehicle restraints is a topic of current public and legislative debate. To better define the effects of restraint systems on injury severity, the following study was undertaken. Parametric statistical tests were used for data analyses. For a 6-month period beginning February 1, 1987, all motor vehicle crash victims treated in the emergency unit were entered into the study (n = 613). There were 290 unrestrained subjects (UR), 254 restrained subjects (R), and 69 were excluded because restraint usage information was unobtainable. Unrestrained victims were younger (mean age, UR = 28, R = 32; p less than 0.05), and were more often male (UR = 65%, R = 51%; p less than 0.05). Hospitalization was more frequently required for unrestrained crash victims (UR = 59%, R = 26%; p less than 0.05). Length of hospital stay (LOS), including ICU confinement, was also extended (mean LOS, UR = 13, R = 10), but this difference did not reach statistical significance. Injury Severity Scores (ISS) and Abbreviated Injury Scales (AIS) were tabulated and compared. Mean ISS was significantly higher for unrestrained victims (UR = 8.28, R = 4.44; p less than 0.05), and a higher proportion of unrestrained victims had scores greater than 15 (UR = 20%, R = 7%; p less than 0.05). Mean AIS was higher in all regions, although the difference did not consistently reach statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of maxillofacial injuries in restrained and unrestrained motor vehicle crash victims

Safety belts reduce the frequency and severity of injuries sustained in motor vehicle crashes. Since the head and face are the most frequently injured anatomic regions in motor vehicle crash victims, the use of active restraints should lessen these injuries. This study was undertaken to examine the ability of safety belts to prevent and alter the pattern of maxillofacial injuries. During a 6-month period beginning February 1, 1987, 613 motor vehicle crash victims presented alive to the Trauma Center at the University of Tennessee Medical Center at Knoxville and were entered into this study. There were 254 restrained victims (R), 290 unrestrained (UR), and 69 who were excluded for lack of sufficient data regarding restraint usage. Unrestrained victims tended to be younger (mean age: UR = 27.9, R = 31.7; p less than 0.03), and more often male (UR = 65% vs. R = 51%; p less than 0.03). Irrespective of position within the vehicle, the mean number of facial lacerations per person was less in the restrained group (R = 0.31, UR = 0.76; p less than 0.03). This injury reduction was more pronounced in front seat occupants (R = 0.27, UR = 0.82; p less than 0.03). Furthermore, a smaller proportion of the lacerations in the restrained group were categorized as complex, i.e., involving more than skin and subcutaneous tissue (R = 5.0%, UR = 15.9%; p less than 0.03). The pattern of skeletal injuries was also significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Human polyomavirus: lack of relationship of viruria to prolonged or severe hemorrhagic cystitis after bone marrow transplant

Urine cytology was studied prospectively for the presence of human polyomavirus (HPV) in 17 consecutive patients undergoing marrow transplantation and correlated with hematuria and hemorrhagic cystitis. Of the 15 evaluable patients, nine had cytologic findings consistent with HPV infection during the first month after transplantation. Of these nine patients, two had gross and seven had microscopic hematuria, all without symptoms of cystitis. Hematuria resolved within 30 days of onset, although three patients had persistent cytologic evidence of HPV until 100 days after transplantation. During the follow-up ranging from 8 to 14 months, none of the patients developed hemorrhagic cystitis. Our data do not support the relationship between HPV and prolonged or severe hemorrhagic cystitis previously suggested by others, nor did we see any late onset hemorrhagic cystitis.

Characterisation of a tamoxifen-resistant variant of the ZR-75-1 human breast cancer cell line (ZR-75-9a1) and ability of the resistant phenotype

A 6-month exposure of ZR-75-1 human breast cancer cells to tamoxifen (1 microM rising to 2 microM). resulted in a fall in oestrogen receptor (ER) levels from 225 fmol mg protein-1 to 56 fmol mg protein-1 while progesterone receptor (PGR) concentration fell from 63 fmol mg protein-1 to undetectable levels. Sensitivity to the anti-proliferative effects of tamoxifen was unchanged. A further 6 months' exposure to 4 microM tamoxifen resulted in loss of detectable ER and PGR and development of resistance to tamoxifen. Resistant cells, designated ZR-75-9a1, displayed morphological changes consistent with the acquisition of a less well differentiated phenotype. Flow cytometric studies demonstrated that the cell cycle distribution pattern of the resistant variant growing in the presence of 8 microM tamoxifen was identical to that of the untreated parent line, which showed marked accumulation of cells in G0/G1 when exposed to 8 microM tamoxifen. The resistant phenotype was not stable if cells were transferred to complete drug-free medium, but remained stable for at least 3 months in the presence of medium lacking oestrogenic activity. ZR-75-9a1 cells differ from previously reported tamoxifen-resistant variants of the MCF-7 line which retain ER and may prove a valuable model for the study of the development and stability of tamoxifen resistance in human breast cancer.

Continuing education: bronchopulmonary dysplasia: management after discharge

Nowhere is the pediatric home health care nurse's knowledge, guidance, and support more crucial than in helping with home management of babies with bronchopulmonary dysplasia, a syndrome of infancy that closely resembles chronic lung disease in adults.

Water availability and trachoma

As part of an epidemiological survey of risk factors for trachoma in 20 villages in the United Republic of Tanzania, we investigated the relationship of village water pumps, distance to water source, and quantity of household water to the risk of inflammatory trachoma. We also evaluated whether there was an association between the cleanliness of children's faces and these water variables. No association was found between the presence of a village water supply and the prevalence of trachoma. However, the risk of trachoma in the household increased with the distance to a water source--although there was no association with the estimated daily amount of water brought into the house. Likewise, children were more likely to have unclean faces if they lived more than 30 minutes from a water source, but whether they had clean faces was not associated with the daily quantity of water brought into the household. The effect of the distance to water supply on trachoma may well reflect the value placed on water within the family, and this determines the priority for its use for hygiene purposes. The results of the study suggest that changing the access to water per se may be insufficient to alter the prevalence of trachoma without also a concomitant effort to change the perception of how water should be utilized in the home.

Design and analysis of experiments on random drift and inbreeding depression

While the genetic consequences of inbreeding and small population size are of fundamental importance in many areas of biology, empirical research on these phenomena has proceeded in the absence of a well-developed statistical methodology. The usual approach is to compare observed means and variances with the expectations of Wright's neutral, additive genetic model for quantitative characters. If the observations deviate from the expectations more than can be accounted for by sampling variance of the parameter estimates, the null hypothesis is routinely rejected in favor of alternatives invoking evolutionary forces such as selection or nonadditive gene action. This is a biased procedure because it treats sequential samples from the same populations as independent, and because it ignores the fact that the expectations of the neutral additive genetic model will rarely be realized when only a finite number of lines are studied. Even when genes are perfectly additive and neutral, the variation among the properties of founder populations, the random development of linkage disequilibrium within lines, and the variance in inbreeding between lines reduce the likelihood that Wright's expectations will be realized in any particular set of lines. Under most experimental designs, these sources of variation are much too large to be ignored. Formulas are presented for the variance-covariance structure of the realized within- and between-line variance under the neutral additive genetic model. These results are then used to develop statistical tests for detecting the operation of selection and/or inbreeding depression in small populations. A number of recommendations are made for the optimal design of experiments on drift and inbreeding, and a method is suggested for the correction of data for general environmental effects. In general, it appears that we can best understand the response of populations to inbreeding and finite population size by studying a very large number (>100) of self-fertilizing or full-sib mated lines in parallel with one or more stable control populations.

Estimation of relatedness by DNA fingerprinting

The recent discovery of hypervariable VNTR (variable number of tandem repeat) loci has led to much excitement among population biologists regarding the feasibility of deriving individual estimates of relatedness in field populations by DNA fingerprinting. It is shown that unbiased estimates of relatedness cannot be obtained at the individual level without knowledge of the allelic distributions in both the individuals of interest and the base population unless the proportion of shared marker alleles between unrelated individuals is essentially zero. Since the latter is usually on the order of 0.1-0.5 and since there are enormous practical difficulties in obtaining the former, only an approximate estimator for the relatedness can be given. The bias of this estimator is individual specific and inversely related to the number of marker loci and frequencies of marker alleles. Substantial sampling variance in estimates of relatedness arises from variation in identity by descent within and between loci and, with finite numbers of alleles, from variation in identity in state between genes that are not identical by descent. In the extreme case of 25 assayed loci, each with an effectively infinite number of alleles, the standard error of a relatedness estimate is no less than 14%, 20%, 35%, and 53% of the expectation for full sibs and second-, third-, and fourth-order relationships, respectively. Attempts to ascertain relatedness by means of DNA fingerprinting should proceed with caution.

Substrate analogue inhibitors of the IgA1 proteinases from Neisseria gonorrhoeae

Substrate analogues based on the amino acid sequence of the hinge region of human IgA1 around the cleavage site of the IgA1 proteinases secreted by Neisseria gonorrhoeae are competitive inhibitors of these enzymes. The octapeptide Thr-Pro-Pro-Thr-Pro-Ser-Pro-Ser, which occurs between residues 233 and 240, has an IC50 value of 0.26 mM for the type 1 proteinase and 0.50 mM for the type 2 enzyme. Acetylation of the octapeptide N-terminal amino group lowers affinity for the type 1 proteinase sixfold but does not change binding to the type 2 enzyme. Amidation of the C-terminal carboxyl group does not change binding to the type 1 proteinase but improves IC50 for the type 2 enzyme. Simultaneous blockade of both the N- and C-termini drastically lowers affinity of the octapeptide for both proteinases. Sequential replacement of the hydroxy amino acids in the blocked octapeptide with cysteine yields a series of inhibitors that generally bind to the neisserial IgA1 proteinases as well as or better than the unblocked octapeptide. The most effective inhibitor contains a cysteine residue at position 6 (P3') and has an IC50 value for the type 2 IgA1 proteinase of 50 microM. Dimerization of the cysteine-containing octapeptides significantly diminishes inhibitory properties. The substrate analogues described here are the first synthetic inhibitors of the neisserial IgA1 proteinases to be reported.

The rate of polygenic mutation

By application of the neutral model of phenotypic evolution, quantitative estimates of the rate of input of genetic variance by polygenic mutation can be extracted from divergence experiments as well as from the response of an inbred base population to selection. The analytical methods are illustrated through a survey of data on a diversity of organisms includingDrosophila, Tribolium, mice, and several crop species. The mutational rate of introduction of genetic variance (Vm) scaled by the environmental variance (VE) is shown to vary between populations, species, and characters with a range of approximately 10−4to 5 × 10−2.Vm/VEforDrosophilaviability is somewhat below this range, while hybrid dysgenesis may temporarily inflateVm/VEbeyond 10−1. Potential sources of bias and error in the estimation ofVmare discussed, as are the practical implications of the observed limits toVm/VEfor projecting the long-term response to selection and for testing adaptational hypotheses.

In vitro neurite extension by granule neurons is dependent upon astroglial-derived fibroblast growth factor

When grown in the absence of astroglial cells, purified mouse cerebellar granule neurons survive less than 36 hr and do not extend neurites. Here we report that low concentrations of basic fibroblast growth factor (bFGF, 1-25 ng/ml) maintained the viability and promoted the differentiation of purified granule neurons. The effect of bFGF on granule cell neurite outgrowth was dose dependent. Neurite outgrowth was stimulated markedly in the presence of 1-25 ng/ml bFGF, but effects were not seen below 1 ng/ml or above 50 ng/ml. When affinity-purified antibodies against bFGF (1-5 micrograms/ml) were added either to purified granule cells or to co-cultures of neurons and astroglial cells, process extension by granule neurons was severely impaired. The inhibition of neurite outgrowth in the presence of anti-bFGF antibodies was reversed by the addition of 25 ng/ml of exogenous bFGF. In addition to neuronotrophic effects, bFGF influenced the rate of growth of the astroglial cells. This result depended on whether the astroglia were grown in isolation from neurons, where low doses of bFGF (10-25 ng) stimulated glial growth, or in coculture with neurons, where much higher doses of bFGF (100-250 ng/ml) were needed for glial mitogenesis. Immunoprecipitation of lysates from 35S-labeled cerebellar astroglial cells with anti-bFGF antibodies revealed a single band after SDS-PAGE at 18,000 Da, the molecular weight of bFGF. These results indicate that glial cells synthesize bFGF and are possibly an endogenous source of bFGF in cerebellar cultures. Thus, astroglial cells synthesize soluble factors needed for neuronal differentiation.

Evolution of intrafamilial interactions

A theory for the evolution of behavioral interactions among relatives is developed that allows for genetic correlations between the types of behavior that are expressed in different social contexts. Both theoretical and empirical considerations indicate that such genetic constraints will almost certainly be common in natural populations. It is shown that when genetic correlations between elements of social behavior exist, Hamilton's rule inaccurately describes the conditions for evolution by way of kin selection. The direction in which social organization evolves is a delicate function of the genetic covariance structure among behaviors expressed as an offspring, sibling, parent, etc. A change in this covariance structure caused by random genetic drift or by a change in environment for a population exhibiting genotype-environment interaction can cause the population to suddenly cross a threshold into a new selective domain. Consequently, radical changes in social organization may arise between closely related species without any major shift in selective pressures external to the population.

Invasive aspergillosis: an unusual cause of hemorrhagic pancreatitis

Advances in chemotherapy have improved survival in patients with hematological malignancies, solid tumors, and have allowed for rapid progress in the field of organ transplantation. However, the frequency of opportunistic, specifically mycotic, infections has risen and provides a new challenge in the treatment of these patients. The following case report illustrates the need for early diagnosis and treatment and is the first known case reported of fatal hemorrhagic pancreatitis secondary to disseminated aspergillosis.

Deep infection in Charnley low-friction arthroplasty. Comparison of plain and gentamicin-loaded cement

A retrospective review of 1542 Charnley low-friction arthroplasties was carried out to compare the incidence of deep infection arising after plain and gentamicin-containing acrylic cement. There was no significant difference between the two series in primary operations, the infection rate being 1.72% and 1.65% respectively. However, in secondary operations (conversions and revisions) the gentamicin-containing cement gave significantly better results--a 0.81% infection rate as compared with 3.46%. All operations were performed in a clean air enclosure using total-body exhaust suits. Radiological diagnosis of deep infection was possible within one year of operation in all cases. Late haematogenous infection occurred in one case and was related to a skin lesion.

The Consequences of Fluctuating Selection for Isozyme Polymorphisms in Daphnia

Temporal sequences of allele frequencies in natural populations of Daphnia are analyzed to obtain the mean and variance of the selection coefficient for both asexual and sexual phases. In general, the alleles at enzyme loci appear to be quasi-neutral. Although significant variation exists for the estimated selection coefficients, the means are in all cases close to zero. Estimates of the variance of selection intensity are applied to existing models to demonstrate the implications of fluctuating selection for the spatial and temporal distribution of gene frequencies in Daphnia. The empirical and analytical results are shown to provide a possible solution to some previously puzzling aspects of Daphnia population genetic surveys. Neither genetic drift nor diversifying selection are necessary conditions for the local diversification of gene frequencies.