Estradiol/progesterone substitution in the luteal phase improves pregnancy rates in stimulated cycles--but only in younger women

Innumerable studies have attempted to demonstrate that hormonal support of the luteal phase during ovulation induction cycles improves pregnancy rates. None has, however, so far been able to confirm the validity of such treatment conclusively, possibly because most studies only utilized progesterone substitution. Since luteal phase endometrium also requires estradiol support, this study attempted to investigate whether hormone substitution with progesterone and estradiol would be more successful in improving pregnancy rates. Amongst approximately 7500 consecutive ovulation induction cycles were identified prospectively which were characterized by a precipitous drop of luteal phase serum estradiol levels by more than 50% over a 48 hour period within 10 days from hCG administration. Those cycles were prospectively randomized to oral micronized estradiol substitution (Group I) or not (Group II), while both groups received routine progesterone substitution of the luteal phase. Cycles were then evaluated in regards to the occurrence of chemical, ectopic and clinical pregnancies. One hundred sixty-three Group I cycles resulted in 34 pregnancies (20.9%), which compared favorably to 21 pregnancies in 167 Group II patients (12.6%) (x2[1] = 4.06; p < 0.04). The advantage for Group I cycles (29/95 pregnancies, 31%) vs. Group II cycles (16/105, 15%) became even more pronounced when only women up to age 35 years were evaluated. Estradiol substitution maintained a significant advantage until age 38 (x2 [1] = 6.87; p < 0.009). While gravidity did not affect pregnancy success, estradiol substitution in Group I benefited nulliparous (23% pregnancy rate) over multiparous women (12% pregnancy rate) (x2 [2] = 6.86; p< 0.03). This association was, however, age-dependent. A combined estradiol and progesterone substitution of the luteal phase of ovulation induction cycles increases the overall pregnancy rate. Since estradiol substitution was initiated in this study only once a precipitous drop in serum estradiol levels had already taken place, an even larger improvement in pregnancy rates could conceivably be possible if earlier estradiol substitution of the luteal phase is initiated. A further expansion of investigations of similar protocols for routine ovulation induction and in vitro fertilization (IVF) cycles may be indicated, especially in women below age 38 years and in nulliparous females.

Factors relating to readmission of term and near-term neonates in the first two weeks of life. Early Discharge Survey Group of the Health Professional Advisory Board of the Greater New York Chapter of the March of Dimes

AIMS

A multisite study of term and near term infants readmitted in the first two weeks of life to 9 New York City area hospitals in 1995 was conducted to evaluate factors related to readmission, including length of newborn stay.

RESULTS

Of the 30,884 infants born at the 9 study hospitals 391 newborns were readmitted. The major admission diagnoses were infection, 40.7%, hyperbilirubinemia, 39.1%, and feeding and/or gastrointestinal problems, 10.5%. In the first week, 65.1% of readmissions were for hyperbilirubinemia and 19.1% were for infection or suspected sepsis. In the second week, 67.8% of readmissions were for infection and 7.6% were for hyperbilirubinemia. Hyperbilirubinemia was the most frequent diagnosis for White and Asian infants, while infection was most frequent for African-American and Hispanic infants. Age at readmission was younger and the interval from discharge was shorter for infants with hyperbilirubinemia. Abnormalities which should have precluded early discharge included feeding difficulties, cyanotic congenital heart defects, hemolytic disease of the newborn, early jaundice or early high bilirubin levels.

CONCLUSION

Attention to identification of infants at risk and programs such as lactation counseling and universal screening for bilirubin (with appropriate interpretation) prior to discharge could have reduced the necessity for readmission regardless of the newborn length of stay.

New alpha-substituted succinate-based hydroxamic acids as TNFalpha convertase inhibitors

Tumor necrosis factor alpha convertase (TACE), the enzyme responsible for the processing of pro-TNFalpha to TNFalpha, has been reported to be a metalloproteinase closely related to matrix metalloproteinases (MMPs). Current inhibitors of TACE such as succinate-based hydroxamic acids exemplified by Marimastat (TACE IC(50): 3.8 nM; blood IC(50): 7 microM) and BB1101 (TACE IC(50): 0.2 nM; blood IC(50): 2.3 microM) suffer from modest potency in blood and poor in vivo properties. The introduction of new bulky alpha-substituents into these succinate-based hydroxamic acids was studied. Substituents such as thioethers, sulfonamides, and ethers showed improved potency against TACE when compared with Marimastat. Although this improvement did not translate into better blood potency for thioether or ether substituents, the sulfonamide series exhibited improved potency both against TACE and in blood when compared with Marimastat. Optimization of this sulfonamide series has culminated in the identification of heterocyclic bicyclic sulfonamides such as 3t (TACE IC(50): 0.57 nM; blood IC(50): 0.28 microM).

Comparison of four components of sensory gating in schizophrenia and normal subjects: a preliminary report

Dysfunction of sensory gating has been implicated in the pathophysiology of schizophrenia. The goal of this study was to provide evidence that sensory gating dysfunction in schizophrenia patients is a compounded problem with difficulty in filtering out irrelevant input and filtering in relevant input at both an early-preattentive stage and a later, early-attentive stage of information processing. Four components of sensory gating were examined in 12 medicated, stable schizophrenia patients and 12 age- and sex-matched normal control subjects. Evoked potential paradigms designed to examine the effects of stimulus repetition and stimulus change were utilized. Attenuation of the amplitude of the P50 and the N100 evoked potentials with stimulus repetition was significantly decreased in schizophrenia patients as compared to normal control subjects. The presentation of deviant stimuli caused the degree of attenuation to decrease in normal subjects. This effect was much decreased (and at times reversed) in schizophrenia subjects. These data suggest that schizophrenia patients have difficulty inhibiting incoming, irrelevant stimuli and responding to incoming, significant input as measured by preattentive EPs (P50). The data also suggest that similar abnormalities can be demonstrated at a slightly later phase of information processing (i.e. early-attentive phase) using the N100 EP.

A susceptibility region for myasthenia gravis extending into the HLA-class I sector telomeric to HLA-C

We have analyzed a series of HLA region markers in 207 UK Caucasoids with early-onset myasthenia gravis (EOMG, onset before age 40), where there is a strong female bias. The well known associations with HLA-DR3 and -B8 have now proved to be significantly stronger in the 165 females than in the 42 males. In patients (of either sex) lacking -DR3, there was also a significant increase in HLA-DR2. Although the muscle weakness in EOMG is clearly mediated by autoantibodies, the associations are consistently stronger with HLA-B8 (in class I) than with HLADR3 (in class II), as confirmed here. We therefore typed 87-137 cases for polymorphisms at four loci in the intervening class III region, and also at three in the adjacent stretch of class I. At each locus, one allele tended to co-occur with HLA-B8 and showed strong and highly significant associations in the patients. There appeared to be a region of maximal susceptibility extending from HSP70 (in class III) past HLA-B and HLA-C at least 600 kb telomerically into the class I region, which is now being mapped in detail. Any candidate genes here that act shortly after puberty may allow more precise localization of susceptibility.

Deficient antibody-dependent cellular cytotoxicity against human immunodeficiency virus (HIV)-expressing target cells in perinatal HIV infection

Peripheral blood mononuclear cells (PBMC) of human immunodeficiency virus (HIV)-infected children, age-matched HIV-seronegative controls, and HIV-infected asymptomatic and symptomatic adults were compared for their ability to mediate antibody-dependent cellular cytotoxicity (ADCC) and natural killer (NK) cell-mediated cytotoxicity against target cells expressing HIV or herpes simplex virus (HSV) antigens. Target cells consisted of CD4 lymphocytes purified from PBMC of HIV-seronegative adults and incubated with the IIIB strain of HIV, HUT78 cells chronically infected with IIIB, and HSV-infected human fibroblasts. PBMC of asymptomatic HIV-infected adults were generally able to lyse CD4 cells expressing HIV antigens. Direct correlation was found between the magnitude of lysis and absolute CD4 cell counts in these individuals. In contrast to these results, PBMC from HIV-infected children were generally unable to lyse IIIB-expressing CD4 cells, regardless of the children's clinical status, age, or absolute CD4 cell counts. Cells from HIV-seronegative adults and children did not directly lyse these target cells either but, in contrast to cells of HIV-seropositive children, were able to mediate cell lysis when serum from an HIV-seropositive adult was added. However, effector cells from these HIV-infected children were able to mediate both ADCC against HSV-infected fibroblasts and NK cell-mediated cytotoxicity against IIIB-infected HUT78 cells. Reduced ability of PBMC from vertically HIV-infected children to mediate ADCC against HIV antigen-expressing CD4 cells may contribute to rapid progression to AIDS.

Estimation of fetal weight in twins: a new mathematical model

OBJECTIVES

Evaluation of new mathematical formula (Femur 4) derived from a twin population to estimate fetal weight in twins using ultrasound. Comparison of Femur 4 is with conventional mathematical models.

DESIGN

Retrospective analysis of ultrasonic measurements of 297 twin babies from 24 to 40 weeks of gestation who were born within 10 days of ultrasound examination.

SETTING

Aberdeen Maternity Hospital.

METHODS

With ultrasonic measurements obtained from twin babies, estimated fetal weight was calculated using the mathematical models of Campbell, Shepard and Hadlock. The calculations were repeated for the model of Femur 4. All models were compared against Femur 4.

RESULTS

The coefficient of determination of the linear regression between the actual and predicted weight was highest for Femur 4 (0.852). Femur 4 had the highest proportion of babies with estimated weights within 10% of actual birthweight (71.4%). In babies who weighed between 2000 and 3000 g, Femur 4 had the least systematic and random error of -1.69 and 8.96, respectively. For babies below the 10th centile for weight, Femur 4 had comparable positive and negative predictive values of 76.0% and 92.3%, respectively. Femur 4 was equally poor at predicting growth discordancy with positive and negative predictive values of 70.0% and 86.5% only.

CONCLUSION

Femur 4 requires measurements of femur length and abdominal circumference only, hence avoiding the need to obtain difficult head measurements which is a common problem in twins. It is a good model for estimation of fetal weight in twins. However, prediction of growth discordancy remains problematic.

Cytomegalovirus seropositivity is associated with the expansion of CD4+CD28- and CD8+CD28- T cells in rheumatoid arthritis

OBJECTIVE

Previous researchers have found expansion of CD4+CD28- T cells in patients with rheumatoid arthritis (RA) compared to age matched controls, and have identified expanded clones of autoreactive cells within this population. We examine the association of prior cytomegalovirus (CMV) infection (positive serum anti-CMV IgG) with the percentage of CD4+CD28- T cells and CD8+CD28- T cells in patients with RA.

METHODS

A total of 45 patients (36 women, 9 men), mean age of 59 years, with definite RA were studied.

RESULTS

In this group 28 patients were seropositive for CMV and 17 seronegative. Seropositive and seronegative subjects did not differ significantly in age, sex, medication use, or severity of disease. Joint count, Health Assessment Questionnaire, pain score, patient global assessment, physician global assessment, and presence of extraarticular disease served to assess disease severity. Expression of CD4/CD28/CD57 and CD8/CD28/CD57 on lymphocytes was determined by 3 color flow cytometry. (CD28 and CD57 are reciprocally related.) CD4+CD28-CD57+ T cells were expanded only in CMV seropositive patients.

CONCLUSION

The "carrier" phenotype that has been hypothesized based on a 2 population model for the distribution of CD4+CD28- T cells in RA can be explained by prior infection with CMV.

Double-blind comparison of lansoprazole 15 mg, lansoprazole 30 mg and placebo as maintenance therapy in patients with healed duodenal ulcers resistant to H2-receptor antagonists

BACKGROUND

Maintenance antisecretory therapy is often used to prevent duodenal ulcer recurrence and control symptoms. This study compared the efficacy and safety of lansoprazole 15 mg and 30 mg daily with placebo in preventing ulcer recurrence in patients with a recent history of duodenal ulcer disease.

METHODS

Fifty-six patients were treated with either lansoprazole 15 mg, 30 mg or placebo o.m.

RESULTS

Within 1 month of study initiation, 27% (four out of 15) of placebo-treated patients experienced ulcer recurrence as compared to 13% (two out of 15) and 6% (one out of 18) of lansoprazole 15 mg and 30 mg treated patients, respectively. Median time to first ulcer recurrence was > 12 months in lansoprazole patients. At Month 12, significantly (P < 0.001) more lansoprazole 15 mg patients (70%) and lansoprazole 30 mg patients (85%) remained healed. Eighty-two per cent of lansoprazole 15 mg and 76% of lansoprazole 30 mg patients remained asymptomatic during the entire study period. All placebo patients became symptomatic, experienced ulcer recurrence, or withdrew from the study by month six. The incidence of adverse events was comparable among the three treatment groups.

CONCLUSIONS

Lansoprazole safely and effectively reduces duodenal ulcer recurrence and ulcer-related symptoms.

Serum from Entamoeba histolytica-infected gerbils selectively suppresses T cell proliferation by inhibiting interleukin-2 production

Suppression of T and B cell responses during invasive amebiasis may be serum mediated. The mechanism of serum-mediated suppression of spleen cell lymphoproliferation from gerbils with amebic liver abscess was examined. Compared with uninfected gerbil serum (10%), serum samples collected at days 10, 30, and 60, but not at day 20 after infection, augmented both concanavalin A (Con A; T cell mitogen)- and lipopolysaccharide (LPS; B cell mitogen)-induced proliferation of homologous spleen cells. Only day 20 serum (>5%) inhibited Con A- but not LPS-induced proliferation of spleen cells from uninfected gerbils. The suppressive mechanism was independent of nitric oxide and prostaglandin but involved reduced interleukin (IL)-2 production. Addition of exogenous IL-2 reversed the suppressive effect of day 20 serum on Con A-stimulated proliferation. These results identify a mechanism whereby serum may contribute to transient suppression of T cell responses during Entamoeba histolytica infections.

Tumors in wild adult raccoons from a suburban area

Images

A survey of infections in United Kingdom laboratories, 1994-1995

AIMS

To identify the number and type of infections occurring in United Kingdom clinical laboratories during 1994 and 1995, following similar surveys covering 1970 to 1989.

METHODS

A retrospective questionnaire survey was undertaken of 397 responding UK clinical laboratories covering 1994 and 1995. A follow up telephone survey was undertaken with each of the laboratories from which a questionnaire had been received indicating a possible or probable laboratory acquired infection during 1994 or 1995.

RESULTS

Questionnaires were sent to 659 laboratories or organisations which were thought to have laboratories, of which 557 responded (response rate of 84.5%). Of these, only 397 were from organisations with laboratories. Over 55,000 person-years of occupational exposure were covered, and only nine cases identified, giving an infection incidence rate overall of 16.2/100,000 person-years, compared with 82.7 infections/100,000 person-years found in a similar survey covering 1988 and 1989, reported previously. Infections were commonest in females, in relatively young staff, in microbiology laboratory workers, and in scientific/technical employees. Gastrointestinal infections predominated, particularly shigellosis, but few specific aetiological factors relating to working practices were identified. No hepatitis B cases were reported.

CONCLUSIONS

The small number of cases identified indicates high standards of infection control, though there is still room for improvement. Periodic studies of this kind are not adequate for comprehensive monitoring of the incidence of laboratory acquired infections. That will require the introduction of a routine, active surveillance programme or prospective survey which has the support and commitment of the laboratories themselves.

Population pharmacokinetics of aminoglycoside antibiotics in patients with cystic fibrosis

The population pharmacokinetics of gentamicin and tobramycin were investigated in a group of 51 young adults with cystic fibrosis. Their ages ranged from 14-35 years, weights from 38-82 kg, and 27 of the patients were female. None of the patients had renal impairment, but 3 patients were treated in the intensive therapy unit (ITU) during one of their courses of therapy. Data comprised 219 courses of therapy and 544 concentrations (mean: 11 per patient). Concentration-time data were analyzed using a nonlinear mixed-effects model package (NONMEM) and were best described by a one-compartment model. Factors identified as potentially influencing aminoglycoside pharmacokinetics were added in a stepwise fashion and the best model found that drug clearance and volume of distribution were related to body surface area and admission to ITU. The mean population estimates were a clearance of 2.89 L/hr/m2 and a volume of distribution of 9.21 L/m2 with a 60% increase in patients who were admitted to ITU. Interpatient variability in clearance and volume were 14% and 8%, respectively. The results suggested that a dose of 120 mg/m2 should achieve an average 1 hour postdose peak of 10 mg/L and trough of <1 mg/L and that higher doses might be required in ITU patients.

Role of cytomegalovirus in the T cell changes seen in elderly individuals

The effect of prior cytomegalovirus (CMV) infection on the immune system was evaluated in young and elderly volunteers. Prevalence of IgG antibodies to CMV was higher in the elderly volunteers. In both age groups, there was a strong association with CMV seropositivity and increased number of CD28- CD4 or CD8 T cells, as well as with increased numbers of T cells expressing CD56 or DR. Although these changes have previously been reported to be age-related, they were independent of age when CMV serological status was taken into account. In contrast, both age group and CMV status were important determinants of the total number of T cells, the number of CD8 T cells, and the number of CD8 T cells expressing CD45RA or CD28. These findings indicate that prior infection with CMV, as reflected by CMV serological status, has important effects on T cell subsets and surface markers and must be considered whenever evaluating age-related changes in immunological parameters.

A fuzzy logic-controlled classifier for use in implantable cardioverter defibrillators

PURPOSE

Implantable cardioverters defibrillators (ICDs) are increasingly used in the management of life-threatening arrhythmias. Correct recognition of a treatable arrhythmia is crucial to this application. However, the computational power of microprocessors currently used in ICDs limits the range of traditional algorithms available for this application.

METHODS

Classification based on fuzzy inference systems (FIS) were trained to recognize different cardiac rhythms (AF, VF, SVT, VT) from the Ann Arbor Electrogram Library. The FIS used were designed using adaptive-network-based fuzzy inference methods to optimize the classification procedure. Only computational techniques suitable for ICD design were used.

RESULTS

After pretraining with the ANFIS correct rhythm classification was observed for the rhythms studied.

CONCLUSION

In this preliminary study, successful rhythm classification was demonstrated using fuzzy logic techniques. In view of the computational efficiency this may have application in ICD design.

Increase in exhaled nitric oxide levels in patients with difficult asthma and correlation with symptoms and disease severity despite treatment with oral and inhaled corticosteroids. Asthma and Allergy Group

BACKGROUND

Patients with difficult asthma suffer chronic moderate to severe persistent asthma symptoms despite high doses of inhaled and oral corticosteroid therapy. These patients suffer a high level of treatment and disease related morbidity but little is known about the degree of airway inflammation in these patients.

METHODS

Fifty two patients were examined to assess levels of exhaled nitric oxide (NO) as a surrogate marker of inflammatory activity in this condition. From this group, 26 patients were defined with severe symptoms and current physiological evidence of reversible airway obstruction requiring high dose inhaled (> or = 2000 micrograms beclomethasone dipropionate (BDP) equivalent) or oral steroid therapy to maintain disease control.

RESULTS

Exhaled NO levels were higher in subjects with difficult asthma (mean 13.9 ppb, 95% CI 9.3 to 18.5) than in normal controls (7.4 ppb, 95% CI 6.9 to 7.8; p < 0.002), but lower than levels in steroid naive mild asthmatics (36.9 ppb, 95% CI 34.6 to 39.3; p < 0.001). Prednisolone treated patients had higher exhaled NO levels than patients only requiring inhaled corticosteroids (17.5 ppb, 95% CI 11.1 to 24.0 versus 7.2 ppb, 95% CI 4.6 to 9.8; p = 0.016), suggesting greater disease severity in this group. Non-compliance with prednisolone treatment was observed in 20% of patients but this did not explain the difference between the treatment groups. Exhaled NO levels were closely correlated with symptom frequency (p = 0.03) and with rescue beta agonist use (p < 0.002), but they did not correlate with lung function.

CONCLUSIONS

Exhaled NO may serve as a useful complement to lung function and symptomatology in the assessment of patients with chronic severe asthma, and in the control and rationalisation of steroid therapy in these patients.

Cultures of sexual adventurism as markers of HIV seroconversion: a case control study in a cohort of Sydney gay men

A case control analysis within an ongoing cohort study was used to examine differences between seroconverters and men who remained HIV-negative. The cases were interviewed within one to 13 months prior to their seroconversion. Their responses to a structured questionnaire were compared with those of HIV-negative controls drawn from the same time period and from the same longitudinal study, Sydney Men and Sexual Health. Data collected from both cases and controls included: demographic and contextual variables, knowledge of HIV transmission, sexual practices, drug and alcohol use and attitudinal factors. The aim was to compare the sexual behaviours, and the social and cultural contexts of such behaviours, of men prior to their HIV seroconversion with men who did not seroconvert. Twenty-three men had seroconverted within the cohort. Cases were identified by a positive HIV antibody test or self-report of positive HIV status following a previous negative HIV test. Three-hundred-and-sixty-nine controls were selected on the basis of being HIV negative at interview in 1994, and having at least one subsequent medically-confirmed negative HIV antibody test. Univariate predictors of seroconversion were: being in a regular relationship with a known HIV-positive partner, drug use, and engaging in a range of anal and esoteric sexual practices. Practices commonly used to enhance sexual pleasure, such as group sex, watching and being watched having sex, the use of sex toys and dressing up/fantasy, were engaged in more frequently by seroconverters. Engaging in these esoteric sexual practices was highly correlated with drug use, involvement in the gay community and engagement in a wide range of anal practices. In the multivariate analysis independent predictors of seroconversion were: younger age; being in a regular relationship with a known HIV-positive partner; believing withdrawal to be safe with regard to HIV transmission; and range of esoteric practices. These results indicate the importance of the social and cultural contexts of particular sexual practices and consequent HIV transmission. Sexually adventurous men may be at increased risk for HIV because they seek sex within particular sexual sub-cultures.

Obstetric events leading to anal sphincter damage

OBJECTIVE

To identify the obstetric factors relating to anal sphincter injury at first vaginal delivery by prospective cohort study of primiparous women.

METHODS

We compared the results of a bowel function questionnaire and anal vector manometry before and 6 weeks after delivery in 184 primiparous women. Postpartum, pudendal nerve conduction latency was measured in all women, and anal endosonography was performed in 81 with altered fecal continence or abnormal physiology.

RESULTS

Sixteen (9%) women, none of whom had altered fecal continence, were delivered by cesarean. After vaginal delivery, 42 of 168 (25%) women had impairment of fecal continence and 76 of 168 (45%) women had abnormal anal physiology. Instrumental vaginal delivery was associated with an 8.1-fold (95% confidence interval [CI] 2.7, 24.0; P < .001) risk of anal sphincter injury and a 7.2-fold (95% CI 2.8, 18.6; P < .001) risk of symptoms. Duration of the second stage of labor beyond 60 minutes led to a 1.7-fold (95% CI 1.14, 2.48; P;< .01) risk of anal sphincter injury and a 1.6-fold (95% CI 1.03, 2.6, P = .01) risk of symptoms. Epidural analgesia, used in 58% of vaginal deliveries, prolonged the second stage of labor (P = .004; odds ratio [OR] 7.7; 95% CI 4.0, 14.7) and was associated with increased risk of sphincter injury (P = .02; OR 2.1; 95% CI 1.1, 4.0) and of symptoms (P = .02; OR 2.0; 95% CI 1.1, 3.7).

CONCLUSION

Instrumental delivery and a second stage of labor prolonged by epidural analgesia are the obstetric factors that pose the greatest risk of injury to the anal sphincter mechanism in primiparous vaginal delivery.

Sulfur isotopic composition of cenozoic seawater sulfate

A continuous seawater sulfate sulfur isotope curve for the Cenozoic with a resolution of approximately 1 million years was generated using marine barite. The sulfur isotopic composition decreased from 19 to 17 per mil between 65 and 55 million years ago, increased abruptly from 17 to 22 per mil between 55 and 45 million years ago, remained nearly constant from 35 to approximately 2 million years ago, and has decreased by 0.8 per mil during the past 2 million years. A comparison between seawater sulfate and marine carbonate carbon isotope records reveals no clear systematic coupling between the sulfur and carbon cycles over one to several millions of years, indicating that changes in the burial rate of pyrite sulfur and organic carbon did not singularly control the atmospheric oxygen content over short time intervals in the Cenozoic. This finding has implications for the modeling of controls on atmospheric oxygen concentration.

Mechanism of rhinovirus-induced changes in airway smooth muscle responsiveness

An important interplay exists between specific viral respiratory infections and altered airway responsiveness in the development and exacerbations of asthma. However, the mechanistic basis of this interplay remains to be identified. This study addressed the hypothesis that rhinovirus (RV), the most common viral respiratory pathogen associated with acute asthma attacks, directly affects airway smooth muscle (ASM) to produce proasthmatic changes in receptor-coupled ASM responsiveness. Isolated rabbit and human ASM tissue and cultured ASM cells were inoculated with human RV (serotype 16) or adenovirus, each for 6 or 24 h. In contrast to adenovirus, which had no effect, inoculation of ASM tissue with RV induced heightened ASM tissue constrictor responsiveness to acetylcholine and attenuated the dose-dependent relaxation of ASM to beta-adrenoceptor stimulation with isoproterenol. These RV-induced changes in ASM responsiveness were largely prevented by pretreating the tissues with pertussis toxin or with a monoclonal blocking antibody to intercellular adhesion molecule-1 (ICAM-1), the principal endogenous receptor for most RVs. In extended studies, we found that the RV-induced changes in ASM responsiveness were associated with diminished cAMP accumulation in response to dose-dependent administration of isoproterenol, and this effect was accompanied by autologously upregulated expression of the Gi protein subtype, Gialpha3, in the ASM. Finally, in separate experiments, we found that the RV-induced effects on ASM responsiveness were also accompanied by autologously induced upregulated mRNA and cell surface protein expression of ICAM-1. Taken together, these findings provide new evidence that RV directly induces proasthmatic phenotypic changes in ASM responsiveness, that this effect is triggered by binding of RV to its ICAM-1 receptor in ASM, and that this binding is associated with the induced endogenously upregulated expression of ICAM-1 and enhanced expression and activation of Gi protein in the RV-infected ASM.

Preparing for the 21st century: diversity in nursing education, research, and practice

This article presents issues surrounding nursing research, education, and practice as they relate to the changing demographics in American society. The authors suggest that cultural diversity should be a key element in all components of nursing. They present challenges to nurse researchers, educators, and practitioners regarding the essential need to be sensitive about cultural diversity. They further suggest that the 21st century will emerge with demographic shifts that include larger groups of ethnic individuals and families. These ethnic groups will be both care providers and recipients of care. Recommendations are suggested to prepare for diversity in America health care systems.

Chlorophyll fluorescence analysis of cyanobacterial photosynthesis and acclimation

Cyanobacteria are ecologically important photosynthetic prokaryotes that also serve as popular model organisms for studies of photosynthesis and gene regulation. Both molecular and ecological studies of cyanobacteria benefit from real-time information on photosynthesis and acclimation. Monitoring in vivo chlorophyll fluorescence can provide noninvasive measures of photosynthetic physiology in a wide range of cyanobacteria and cyanolichens and requires only small samples. Cyanobacterial fluorescence patterns are distinct from those of plants, because of key structural and functional properties of cyanobacteria. These include significant fluorescence emission from the light-harvesting phycobiliproteins; large and rapid changes in fluorescence yield (state transitions) which depend on metabolic and environmental conditions; and flexible, overlapping respiratory and photosynthetic electron transport chains. The fluorescence parameters FV/FM, FV'/FM',qp,qN, NPQ, and phiPS II were originally developed to extract information from the fluorescence signals of higher plants. In this review, we consider how the special properties of cyanobacteria can be accommodated and used to extract biologically useful information from cyanobacterial in vivo chlorophyll fluorescence signals. We describe how the pattern of fluorescence yield versus light intensity can be used to predict the acclimated light level for a cyanobacterial population, giving information valuable for both laboratory and field studies of acclimation processes. The size of the change in fluorescence yield during dark-to-light transitions can provide information on respiration and the iron status of the cyanobacteria. Finally, fluorescence parameters can be used to estimate the electron transport rate at the acclimated growth light intensity.

Effects of daunomycin implants on filtering surgery outcomes in rabbits

PURPOSE

To evaluate the effects of a novel daunomycin (DM) implant on intraocular pressure (IOP), bleb survival, and anterior segment complications when administered during filtering surgery on New Zealand White rabbits.

METHODS

Implants were prepared by covalent coupling of DM to a high molecular weight hyaluronic acid (HA) and fabricated into solid implants containing 250, 65, and 25 microg of DM. Full thickness sclerostomies were performed, and rabbits received no implant (control), placebo implant containing HA, or an implant containing HA-DM conjugate at the time of surgery. Rabbits were then followed for 30 days to assess change in IOP, bleb survival, and anterior segment associated complications.

RESULTS

In vitro, the release of DM from the implants was a first order process with a half-life of 51 h. In control rabbits, rabbits receiving placebo implant, and rabbits receiving HADM (250 microg) implants, the mean IOPs on day 3 were 11.1 +/-1.6, 10.8 +/- 2.7, and 14 +/- 0.98 mm of Hg, respectively. On days 5 through 9, IOP in the control and placebo-implanted groups returned to preoperative levels. However, in rabbits receiving 250 microg of conjugated DM, mean IOP on day 7 was reduced from preoperative levels by 11.8 +/- 3.2 mm of Hg (P < 0.05). This reduction in IOP was significantly different (P < 0.05) from both control and placebo implant groups, and IOPs remained at these levels until studies were terminated on day 30. In control and placebo-implanted rabbits, bleb size started decreasing on day 1, and by day 7, no blebs were observed. In rabbits receiving 250 microg HA-DM implants, mean bleb survival time was greater than 30 days. The DM-induced reduction in IOP and enhanced bleb survival was dose-dependent. In rabbits receiving 65 microg of conjugated DM, lOPs were significantly reduced through day 30; however, at times beyond day 19 there was a gradual rise in mean IOP as filtering procedures in individual animals began to fail. Mean bleb survival time was greater than 30 days for implants containing 65 microg of conjugated DM. In rabbits receiving HA-DM implant containing 25 microg of DM, IOPs were not significantly different from preoperative levels beyond day 9, and no significant enhancement in bleb survival was observed in these animals. Comparison of HA-DM conjugated implants to those containing equal doses of free DM demonstrated that the mean IOP change at 30 days were similar; however, there was a reduction in anterior segment complications associated with the use of HA-DM conjugated implants.

CONCLUSIONS

This study provides evidence that the controlled release of DM when conjugated to HA can significantly improve the success of filtering procedures. The maintenance of ocular hypotension and bleb survival along with the reduction in anterior segment complications supports the idea that HA-DM conjugate will be more efficacious than the use of free DM in improving the success rate of filtering surgery.