alpha-Cell neogenesis in an animal model of IDDM

Currently there is debate regarding the capacity of pancreatic islets to regenerate in adult animals. Because pancreatic endocrine cells are thought to arise from duct cells, we examined the pancreatic ductal epithelium of the diabetic NOD mouse for evidence of islet neogenesis. We have evidence of duct proliferation as well as ductal cell differentiation, as suggested by bromodeoxyuridine-labeling and the presence of glucagon-containing cells within these ducts. In addition, the ductal epithelia in diabetic NOD mice expressed the neuroendocrine markers neuropeptide Y and tyrosine hydroxylase. These ducts also expressed the homeobox gene product, insulin promoter factor 1. Ductal cell proliferation and expression of these markers was not observed in transgenic NOD mice (NOD-E), which do not develop clinical or histopathological symptoms of IDDM. This suggests that the observed ductal cell proliferation and differentiation was a direct result of beta-cell destruction and insulin insufficiency in these adult diabetic mice, which further suggests that these events are recapitulating islet ontogeny observed during embryogenesis. It is possible that comparable processes occur in the human diabetic pancreas.

Laparoscopic-assisted vaginal hysterectomy: American Association of Gynecologic Laparoscopists' 1995 membership survey

A questionnaire was mailed to all members of the AAGL to determine the current performance of laparoscopic-assisted vaginal hysterectomy (LAVH), and to assess the relative frequencies of techniques and complications. Answers of the 1092 members who responded were entered into a database computer program and analyzed. The analysis revealed 14,911 LAVHs performed by 767 members. Complication rates appeared to be in the same range as those reported for vaginal hysterectomy and total abdominal hysterectomy. Inferior epigastric injury was the most common complication. Physicians showed a shift in their practices away from abdominal hysterectomy after they learned LAVH.

The earnings experience of rural-urban migrants in Korea

"Migration models in the Harris-Todaro tradition imply that urban informal sector earnings are less than rural sector earnings. Examining the situation for [South] Korea, we find that both urban formal and informal sector earnings exceed earnings opportunities in rural areas, making rural-urban migration the best decision for the individual and for the Korean economy in terms of maximizing output.... The implication for policy makers is that government efforts may be better directed toward mitigating the externalities caused by over-crowding, rather than attempting to influence population movements."

Tolerance and suppression in a primed immune system

The induction of tolerance in a primed immune system would be valuable therapeutically, but has been difficult to achieve. Mice primed to multiple minor histoincompatible antigens (minors) are able to rapidly reject secondary grafts using either their CD4+ or CD8+ T-cell subpopulations. Short courses of treatment with nonlytic anti-CD4 and anti-CD8 antibodies targeted at both T-cell subsets can induce long-term peripheral T-cell tolerance in primed mice. We examine the mechanisms by which peripheral tolerance is maintained, and show that tolerant mice harbor CD4+ T cells capable of specifically suppressing rejection mediated by either subset of primed T cells. Remarkably, elimination of CD4+ T cells from tolerant mice resulted in graft rejection, suggesting that graft-reactive CD8+ T cells had not been eliminated, but had been under continuous regulation by "tolerant" CD4+ T cells. This result demonstrates that it may be possible to establish therapeutic operational tolerance without permanently inactivating all antigen-reactive cells.

CD4 mAbs prevent progression of alloactivated CD4+ T cells into the S phase of the cell cycle without interfering with early activation signals

Knowing that several CD4 mAbs may delay allograft rejection in the absence of circulating CD4+ lymphocyte depletion in vivo, we investigated the mechanisms whereby CD4 mAbs can interfere with the development of alloreactive T cells in the mixed lymphocyte reaction (MLR). In agreement with previous reports, CD4 mAbs of different species (mouse, rat, humanized), isotypes (IgG1, IgG2a, and IgG2b) and different epitope specificities decreased 3H-TdR incorporation in MLR, using monocyte-depleted or CD4+ T lymphocyte-enriched blood mononuclear cells as responders. Those effects were achieved at nonsaturating mAb concentration and were still demonstrable upon delayed addition of CD4 mAbs. However, CD4 mAbs decreased neither the number of blast cells nor the expression of CD25 (the alpha chain of IL-2 receptor), indicating that initial activation events leading to blast transformation were not affected. Determination of cytokine gene expression by non competitive quantitative RT-PCR and measurement of protein concentration in supernatants demonstrated that CD4 mAbs did not decrease IFN-gamma induced by alloactivation. However IL-2 concentration was decreased in all supernatants whereas IL-2 mRNA expression, only slightly decreased at 24 hr, and dropped after 72 hr. IL-5 and IL-10 mRNAs, equally expressed by stimulated or nonstimulated responder cells, were not affected by CD4 mAbs. IL-4 mRNA was not detectable. Furthermore, addition of rIL-2, rIFN-gamma or rIL-4 did not overcome proliferation inhibition. The data provide a novel insight into the mechanisms of CD4 mAbs immunosuppresssion that associates a decrease of IL-2 expression with an IL-2 resistant blockade of the progression of activated CD4+ T cells from the G1 to the S phases of the cell cycle.

Prevalence and prediction of positive discrepancy creation: examining a discrepancy between two self-regulation theories

The conflicting perspectives of control theory (CT) and self-efficacy theory (SET) concerning positive discrepancy creation (PDC) were tested and are discussed. According to CT, discrepancies between past performance and future goals are continually reduced. This is contrary to SET's focus on setting future goals higher than past performance levels. Participants performed several trials in a multitask environment, during which they did as many or as few problems as they chose on each of 4 intellectual tasks. Results suggest that PDC is not uncommon in a multitask environment, even after extensive task experience. Regression decomposition techniques identified 2 types of PDC: goal driven and performance driven. Need for achievement, instrumentality, and expectancy predicted the 2 types of PDC with varying success across the 4 tasks. The 2 types of PDC reflect the different theoretical approaches and these 2 self-regulation theories.

Outcome of surgical decompression of the second cervical root for cervicogenic headache

OBJECTIVE

There is limited information on the surgical treatment of cervicogenic headache (CH). The objective of this study is to analyze the utility of microsurgical decompression of the second cervical (C2) root and ganglion as a treatment for CH.

METHODS

Thirty-nine sequential C2 root and ganglion decompressions, performed for the treatment of CH on 35 patients at the Dartmouth-Hitchcock Medical Center during a 70-month period, were analyzed retrospectively. Preoperative factors and intraoperative findings were evaluated with respect to outcome.

RESULTS

At a mean follow-up of 21 months, 12 patients (13 sides) were pain free, and 15 were adequately improved (18 sides). Treatment eventually failed in eight patients. No patient, however, was worse after surgical intervention. There was no major morbidity or mortality associated with the operation. The eight patients with unsatisfactory outcome were evaluated for a possible second operation, and four underwent it. One patient of the four is pain free after 28 months, and two gained adequate improvement at 3 and 12 months. The fourth patient required a third operation but has achieved adequate relief at 6 months. Thus, the overall success rate (either pain free or with adequate improvement) was 90%. No specific prognostic factors could be established, other than the accepted diagnostic criteria and successful anesthetic blockade of the C2 root and ganglion.

CONCLUSION

The results suggest that microsurgical decompression of the C2 root and ganglion has some utility in treating CH. The accepted diagnostic criteria and success of anesthetic blockade of C2 should identify the subset of patients with CH predominantly caused by C2 root or ganglion effect at this level, which may favor surgical treatment.

Performance traits, hoof mineral composition, and hoof characteristics of bulls in a 112-day postweaning feedlot performance test

OBJECTIVE

To evaluate relations between hoof and performance data from bulls fed in a 112-day standardized postweaning feedlot performance test. ANIMALS AND DESIGN: Breeds included were Angus (n = 20), Brangus (n = 19), Hereford (n = 31), and Simmental (n = 53). Hoof measurements, scores, and a 0.5-g hoof tissue sample were obtained from the right forefoot of bulls on days 1 and 112 of 4 tests conducted in 3 locations in Arkansas. Data were analyzed, using least squares ANOVA. The model used included an overall mean, breed, farm of origin within breed, initial age, and initial weight within breed and residual. Residual and canonical correlations of the traits studied were calculated.

RESULTS

Residual correlations were found between some hoof minerals. Canonical correlations between performance traits and hoof minerals, between hoof characteristics and hoof minerals, and between hoof characteristics and performance traits were 0.62 and 0.45 (P < 0.005), 0.54 and 0.40 (P < 0.05), and 0.56 (P < 0.01) and 0.26 (P > 0.05), respectively.

CONCLUSIONS

These data suggest that a relation exists between performance traits and hoof mineral composition and hoof characteristics and mineral composition. The visual scoring system for these data did not genetically separate bulls on the basis of claw quality.

CLINICAL IMPLICATIONS

By selecting bulls with high claw quality, cattle producers are decreasing the chances of premature culling because of hoof laminitis. Therefore, by obtaining hoof measurements and mineral composition in a feedlot performance test, producers should have the tools to select bulls for increased lifetime performance.

Advance directive decision making among medical inpatients

Per the Patient Self-Determination Act of 1991, hospitals are required to ascertain whether patients have an advance directive (AD). At this point, factors prompting patients to issue ADs have not been studied. The purpose of this study was to describe patients' understanding of ADs as well as the process patients used to arrive at their decisions to implement an AD. A stratified random sample of 26 patients from two intensive care units, one general medical unit, one general cardiac unit, and one acquired immunodeficiency unit were selected for participation. Patients were asked a series of open-ended questions to determine their knowledge and understanding of ADs. The constant comparative method was used to review the transcripts. It was found that only 31 per cent of patients had issued an AD, and 20% had learned of ADs for the first time during their hospitalization. Response analysis showed four phases of AD decision making: evaluation of illness, establishment of priorities, consideration of implications of the directives, and selection or rejection of directives. In conclusion, patients continue to have limited understanding of ADs and their implications. Continued investigation will elucidate the best strategies to educate patients about this topic.

Characteristics of patients successfully treated for cervicogenic headache by surgical decompression of the second cervical root

We have recently reported 90% success in a series of patients undergoing microsurgical decompression of the second cervical (C2) nerve root and ganglion for cervicogenic headache. Review and analysis of our database was carried out in order to cull factors characterizing patients amenable to this surgical treatment. Thirty-five sequential C2 decompressions performed on 31 patients who were pain-free or significantly improved in follow-up were evaluated retrospectively. Preoperative factors and intraoperative findings were analyzed for prognostic significance. The diagnosis of cervicogenic headache was made using established criteria and success of CT-guided C2 anesthetic blockade in alleviating the headache. Numerous historical factors noted preoperatively including age, sex, history of trauma, autonomic symptoms, visual changes, and many others were not able to be well correlated with outcome in univariate analysis. Likewise, no strong correlation could be made for findings on physical examination. Thus, no specific prognostic factors could be established, other than the accepted diagnostic criteria and successful anesthetic blockade of the C2 root and ganglion. These factors should identify the subset of patients with cervicogenic headache predominantly due to C2 root or ganglion effect and thus may favor a surgical treatment.

Antenatal diagnosis and management of fetomaternal alloimmune thrombocytopenia

Fetomaternal alloimmune thrombocytopenia (FMAT) arises from maternal-fetal platelet antigen incompatibility, which stimulates the production of maternal immunoglobulin G (IgG) platelet-specific antibody. Transplacental passage of this antibody results in fetal platelet destruction and consequent thrombocytopenia. Sequelae of thrombocytopenia may be observed in both the fetus and neonate with intracranial hemorrhage occurring in approximately 10 to 30% of affected infants. No antenatal universal screening test is currently available to detect the 50% of cases occurring in the first pregnancy. The recurrence rate in subsequent pregnancies is 75 to 85%, with a tendency to increasing disease severity. Paternal platelet genotyping is recommended to assist in risk counseling following an affected pregnancy. Prenatal therapeutic strategies are aimed at elevating the fetal platelet count in affected pregnancies and thus decreasing hemorrhagic sequelae. The most effective treatment regimen is uncertain, but encouraging results are reported with the use of maternal intravenous gamma globulin. We report our experience in the antenatal diagnosis and management of FMAT.

Adherence to breast cancer screening guidelines among African-American women of differing employment status

The purpose of this study was to identify and compare the adherence to breast cancer screening guidelines [monthly breast self-examination (BSE), age-related mammography, yearly professional breast examination (PBE)] among African-American women (AAW) of differing employment status. The Breast Cancer Screening Model served as the organizing framework for this study. One hundred fifty-four subjects were quota sampled according to age and employment group status. Findings showed that 63% of all subjects practiced monthly BSE and 76% had undergone a yearly PBE. Only 20% of all subjects had undergone a mammogram according to the age-related guidelines. Overall, breast cancer screening rates were lower than recommended across all employment groups. Variables that uniquely explained 74% of the variance in monthly BSE included level of education, marital status, social influence, knowledge of BSE, and intention to do BSE in the future. Age group, previous instruction on mammography, income, and perceived barriers related to mammography explained 15% of the variance in age-related mammography. Finally, marital status, previous information on PBE, and intrinsic motivation explained 42% of the variance in yearly PBE. Together, these findings highlight the need for (a) the development of strategies that will promote long-term adherence to all three screening guidelines, and (b) the design of qualitative studies using a representative sample of AAW of differing socioeconomic backgrounds.

Operative hysteroscopy: American Association of Gynecologic Laparoscopists' 1993 membership survey

The 1993 American Association of Gynecologic Laparoscopists' membership survey on operative hysteroscopy had 713 respondents reporting 14,707 procedures. Directed biopsy and endometrial ablation were the most commonly reported. The majority of operative hysteroscopies were performed for a complaint of abnormal bleeding (78%). The most frequent reported complication was uterine perforation not requiring transfusion (14.2/1000 procedures). The rates of water intoxication and pulmonary edema stayed essentially unchanged from 1991: 2/1000 in 1993 compared with 1.4/1000 in 1991. No deaths were reported this year. The consistency in rates of procedures performed and complications within the three surveys conducted in 1988, 1991, and 1993 add credibility to the data from these retrospective studies.

Laparoscopic sterilization: American Association of Gynecologic Laparoscopists' 1993 membership survey

The 1993 membership survey of the American Association of Gynecologic Laparoscopists received 938 responses, or 13% of the membership. The surgeons reported performing 22,966 sterilizations and 36,482 diagnostic procedures. The distribution of sterilization techniques has remained stable since 1985. Complication rates associated with diagnostic procedures remain consistently higher than those with sterilizations. One death was reported from sterilization, none for diagnostic procedures.

Operative laparoscopy: American Association of Gynecologic Laparoscopists' 1993 membership survey

The American Association of Gynecologic Laparoscopists' 1993 membership survey on operative laparoscopy had 825 respondents reporting 45,042 procedures. The most frequent indication was pelvic pain (56% of procedures), followed by infertility (38%). There were 7382 laparoscopically assisted hysterectomies reported. Compared with 1988 and 1991 survey data, the rates of unintended laparotomy, hemorrhage, and bowel or urinary tract injury increased, but the overall complication and death rates remained essentially unchanged.

Research for improving the health and well-being of the black community: implications for shaping a research agenda

Black Americans continue to experience a disproportionately poorer health status than the majority population. Research is one avenue that can help to identify both contributing and mediating factors related to this disparity. Black nurses are in a unique position to conduct research that will improve the health and well-being of Black Americans. This article addresses the need for Black nurses to become more actively involved in designing, conducting, and evaluating research, and identifies areas for consideration when shaping a research agenda for the Black community.

Critical appraisal of research literature by expert and inexperienced physical therapy researchers

BACKGROUND AND PURPOSE

In this study, critical appraisal skills of physical therapists who were inexperienced and expert researchers were compared and the effect of the following independent variables on the appraisal skills of novices was examined: years of physical therapy practice, postgraduate experience with research, level of comfort with research, journal reading habits, and content-specific expertise.

SUBJECTS AND METHODS

Four expert and 20 inexperienced researchers critiqued the same research article. A content analysis of the expert critiques was used to develop a set of 12 items of concerns about the study.

RESULTS

Experts identified a mean of 7.75 items of concern; novices identified a mean of 3.95 items. For 10 of the 12 items, a greater proportion of experts identified each concern compared with the novices. Novices had comparatively less difficulty identifying concerns with internal validity than they did identifying issues relating to construct validity. Only one of the variables--content-specific expertise--was associated with differences in critical appraisal skills among the novices.

CONCLUSION AND DISCUSSION

These finding suggest that analysis of construct issues in research articles is a more advanced skill than analysis of research design and that critical appraisal of research literature is enhanced by clinical experiences related to the subject of the research report.

Operative laparoscopy: American Association of Gynecologic Laparoscopists, 1993 membership survey

The American Association of Gynecologic Laparoscopists' 1993 membership survey on operative laparoscopy had 1205 respondents reporting 80,031 procedures. Diagnostic laparoscopy remains the most common procedure, followed by adhesiolysis and laparoscopically assisted vaginal hysterectomy. This survey was particularly designed to chronicle the rate of complications as increasingly complex laparoscopic procedures are performed.

Efficacy of Brahman breeding in the management of insecticide-resistant horn flies (Diptera: Muscidae) on beef cattle

The efficacy of Brahman breeding used as an alternative tactic to manage insecticide-resistant populations of adult horn flies, Haematobia irritans irritans (L.), was determined. Concentration-mortality bioassays done at Booneville and Hope, AR, in 1988 and 1989, respectively, showed that horn fly populations were resistant to diazinon, pirimiphos methyl, tetrachlorvinphos, and methoxychlor. Data showed loss of field efficacy for coumaphos and delnav. Mean horn fly counts on Braham cows were significantly lower than on Angus cows for all sampling dates in 1989 and 1990. Mean fly counts on Brahman x Angus cows were approximately intermediate to the two purebred mean fly counts. Brahman breeding caused significant reductions in the number of organophosphate-resistant horn flies, which had been equal to or greater than that obtained from continued spraying with organophosphate insecticides. The Brahman x Hereford cows, which have one-eighth greater Brahman breeding than the Brangus cows, had fewer horn flies on 48 of 56 sampling dates in 1988-1990 and significantly fewer flies on 37 sampling dates. The effectiveness of Brahman breeding in causing lower numbers of insecticide-resistant horn flies significantly increased as the percentage of Brahman breeding increased.

Operative hysteroscopy. American Association of Gynecologic Laparoscopists 1991 membership survey

The 1991 American Association of Gynecologic Laparoscopists membership survey on operative hysteroscopy had a total of 630 respondents (almost double the 1988 number) who reported performing 17,298 procedures as compared to 7,293 in 1988. Directed biopsy and endometrial ablation were the procedures reported most commonly. Endometrial ablation increased fivefold since 1988, and myomectomy increased fourfold. The majority of operative hysteroscopies were performed for a complaint of abnormal bleeding (73%). The most frequently reported complication was uterine perforation not requiring transfusion (11 per 1,000 procedures). The rate of water intoxication or pulmonary edema dropped from 3.4/1,000 in 1988 to 1.4/1,000 in 1991. However, some serious complications (eight laparotomies for bowel injury, three CO2 embolisms and three deaths) were reported for 1991.

Laparoscopic sterilization. American Association of Gynecologic Laparoscopists 1991 membership survey

The 1991 membership survey of the American Association of Gynecologic Laparoscopists indicated more laparoscopic procedures than had been reported in the last survey, in 1988. The respondents reported 30,480 sterilizations, 41,160 diagnostic laparoscopies and 8,015 hysteroscopies. The distribution of sterilization by method of tubal occlusion has remained stable since 1985. Complications from diagnostic laparoscopy remain consistently higher than from sterilization. This year the complication rate for diagnostic procedures was higher than in any other year since 1976 (4.9 per 1,000 cases). One death was reported after sterilization and one after diagnostic laparoscopy.

Operative laparoscopy. American Association of Gynecologic Laparoscopists 1991 membership survey

The American Association of Gynecologic Laparoscopists 1991 membership survey on operative laparoscopy had a total of 878 respondents reporting 56,536 procedures, for a 1.5-fold increase over the number of procedures reported in 1988. The most frequent indication was pelvic pain (58% of procedures); next was infertility (42%). Laparoscopic management of ectopic pregnancy increased over twofold, from 1,914 cases in 1988 to 4,620 in 1991. As compared to the 1988 survey data, the rate of unintended laparotomy to manage hemorrhage, bowel or urinary tract injury may have increased, but the death rate remained low, 1.8 per 100,000 procedures.

Combined analysis of tall fescue steer grazing studies in the Eastern United States

The mixed-models procedure (MMP) was used to analyze pooled data sets from 12 independent studies conducted during the last 13 yr at nine locations in seven states to provide combined estimates of daily gains by beef steers (Bos taurus) grazing tall fescue (Festuca arundinacea Schreb.) pastures free of (E-) or infested (E+) at different levels with the endophytic fungus Acremonium coenophialum. Treatments included low-infestation (< or = 5% E+), moderate-infestation (> or = 20 to < or = 35% E+), and high-infestation (> or = 50 to < or = 97% E+) tall fescue pastures, and, in tall fescue-clover (Trifolium spp.) mixtures, pastures at the same E+ levels with approximately 25 and 10% clover in spring and summer stands, respectively. Spring, summer, and combined spring+summer data were analyzed separately. The MMP permitted estimation of the fixed effects of treatments over a broad inference space of future years and different tall fescue pastures over a wide geographic range; detected relationships that had not been apparent in the individual studies, such as the interactions between clover presence and E+ infestation levels; and provided a more coherent body of information than did the results obtained from each discrete study. Logistical and financial constraints that force undesirable compromises in the conduct of future grazing and other expensive or time-consuming research may be avoided by using MMP within the context of cooperative projects.

Single-Crystal Epitaxial Thin Films of the Isotropic Metallic Oxides Sr1-xCaxRuO3 (0 le x le 1)

Single-crystal epitaxial thin films of the isotropic metallic oxides Sr1-xCaxRuO(3) (0 </= x </= 1) were grown on miscut SrTiO(3)(100) substrates in situ by 90 degrees off-axis sputtering. These thin films exhibit low isotropic resistivities, excellent chemical and thermal stability, good surface smoothness, and high crystalline quality. Furthermore, the lattice parameters and magnetic properties can be varied by simply changing the strontium/calcium ratio. These epitaxial thin films, and their multilayer structures with other oxide materials, can be used for the fabrication of superconducting, ferroelectric, magneto-optic, and electro-optic devices.