P577Early experience with the first pacemakers to directly connect with smart devices for remote monitoring

Background

Remote monitoring is associated with improved patient outcomes; however, adoption and adherence to remote monitoring via home-based consoles remains suboptimal. BlueSync technology in new generation pacemaker and CRT-P models enables the implanted device to communicate directly with patient-owned, Bluetooth-equipped smartphones/tablets and an app (MyCareLink Heart). The app can automatically retrieve information from the cardiac device and transmit the data to the remote network, eliminating the need for traditional remote monitoring consoles.

Objectives

To characterize the communication process between implanted pacemakers and smart device remote monitoring apps by assessing the success of prescheduled remote transmissions in the first month of follow-up. Additionally, to assess the feedback of both patients and clinicians about the process of device pairing.

Methods

Enrollment in the BlueSync Field Evaluation began in April 2018 and was completed November 2018. Follow-up is ongoing. Prior to enrollment in the evaluation, patients completed the device pairing process with the app using their own compatible smartphone or tablet. Patient and clinician questionnaires were completed at the time of the device pairing process. After enrollment, successful completion of scheduled transmissions occurring in the first month were analyzed.

Results

Preliminary data includes 241 enrolled patients with mean age of 64.7±15.5 yrs (min 20, max 90 yrs), who completed device pairing between their implanted device and their smart device app. Of enrolled patients, 79% felt that the device paring was easy to do, 85% were satisfied with the amount of time it took to complete it, and 93% felt that they would be comfortable using the app. Clinicians reported that 67% of the device pairings took less than 20 minutes and 78% felt patients would be able to use the app independently. At the time of analysis 174 patients had at least one scheduled transmission within the first month, and collectively had a total of 322 scheduled transmissions. Out of these, 309 (96%, 95% CI: 93%-98%) were successfully completed.

MyCareLink Heart App

Conclusions

Initial experience with the world's first app based remote monitoring system for Bluetooth enabled pacemakers demonstrated success to scheduled transmissions in the first month across a wide range of patient ages. Patients and clinicians reported high satisfaction with this novel technology.

Acknowledgement/Funding

Medtronic PLC

Abstract P2-14-01: The impact of local therapy on locoregional recurrence in women with high risk breast cancer in the neoadjuvant I-SPY2 TRIAL

Background: In women with breast cancer receiving neoadjuvant chemotherapy, residual cancer burden (RCB) predicts distant recurrence and survival. In those with high risk tumors, locoregional recurrence (LRR) remains a concern, and has been associated with type of local therapy received. We evaluated the impact of local therapy on LRR in the ISPY-2 TRIAL.

Methods: Data were analyzed in Stata 14.2, using Chi2 test, log rank test, and a Cox proportional hazards model. RCB was considered a categorical variable (0/1 versus 2/3), as described in prior publications. Breast surgery categories were lumpectomy +/- radiotherapy, or mastectomy +/- radiotherapy. Axillary surgery was defined as sentinel lymph node (SLN) surgery (≤6 nodes removed) or axillary dissection (>6 nodes).

Results: Follow up data from the I-SPY2 TRIAL were available for 630 patients (median follow up 2.76 yrs, range 0.4-7.2). Type of local therapy was significantly associated with clinical stage at presentation, with stage III patients most frequently undergoing mastectomy + radiation (p<0.001). Women with higher RCB were more likely to undergo mastectomy than those with lower RCB (61.3% vs 48.8% mastectomy rate, p=0.002), and more likely to receive adjuvant radiotherapy (62.0% vs 53.9%, p=0.048). There was no association between clinical stage, type of surgery, or radiotherapy and LRR (Table). Higher RCB was significantly associated with LRR, with 3 year locoregional recurrence free rate of 95.1% in RCB 0/1 versus 89.9% in RCB 2/3 (p=0.003).

In a Cox model adjusting for clinical stage, tumor subtype, surgical therapy, RCB status, nodal radiation, and age, significant predictors for LRR were tumor subtype and RCB status. Hazard ratio (HR) for LRR in those with RCB 0/1 was 0.39 compared to those with RCB 2/3 (95% CI 0.17-0.87, p=0.021). There was no difference in LRR between breast conservation and mastectomy; within the breast conservation group, those who had lumpectomy alone had higher hazard of LRR compared to those having lumpectomy + radiation (HR 3.1, 95% CI 1.1-9.2, p=0.043).

Conclusions: Extent of surgical therapy was not associated with local tumor control, regardless of advanced tumor stage at presentation. Rather, tumor biology and response to therapy were the best predictors of LRR. These data highlight the opportunity to minimize the morbidity of extensive surgical therapy for patients with excellent response to systemic therapy.

LRR rates by clinical features and treatment status FrequencyLRR RateP valueClinical Stage  0.5I240 (47.5%)5.8% II185 (36.6%)8.7% III80 (15.8%)6.3% Tumor Subtype  0.014ER+PR+Her2-161 (26.4%)3.1% ER+PR-Her2-56 (9.2%)3.6% Her2+176 (28.9%)6.3% Triple negative216 (35.5%)11.1% Local therapy  0.169Lumpectomy85 (13.5%)11.8% Lumpectomy with radiation198 (31.4%)5.6% Mastectomy173 (27.5%)5.2% Mastectomy with radiation174 (27.6%)8.6% Axillary surgery  0.23None5 (0.8%)20% SLN329 (52.2%)5.8% ALND296 (47%)8.5% Axillary radiation  0.535Yes42 (6.7%)9.5% No588 (93.3%)7.0% Axillary management  0.2No surgery or radiation5 (0.8%)20.0% SLN312 (50%)5.3% SLN+Axillary radiation17 (2.7%)8.3% ALND271 (43%)10.3% ALND+Axillary radiation25 (4%)5.4% RCB  0.0020/1293 (50.1%)3.8% 2/3292 (49.9%)10.3% 

Citation Format: Silverstein J, Suleiman L, Yau C, Price ER, Singhrao R, Yee D, DeMichele A, Isaacs C, Albain KS, Chien AJ, Forero-Torres A, Wallace AM, Pusztai L, Ellis ED, Elias AD, Lang JE, Lu J, Han HS, Clark AS, Korde L, Nanda R, Northfelt DW, Khan QJ, Viscusi RK, Euhus DM, Edmiston KK, Chui SY, Kemmer K, Wood WC, Park JW, Liu MC, Olopade O, Leyland-Jones B, Tripathy D, Moulder SL, Rugo HS, Schwab R, Lo S, Helsten T, Beckwith H, I-SPY 2 TRIAL Consortium, Berry DA, Asare SM, Esserman LJ, Boughey JC, Mukhtar RA. The impact of local therapy on locoregional recurrence in women with high risk breast cancer in the neoadjuvant I-SPY2 TRIAL [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-14-01.

Endocrine effects of growth hormone overexpression in transgenic coho salmon

Non-transgenic (wild-type) coho salmon (Oncorhynchus kisutch), growth hormone (GH) transgenic salmon (with highly elevated growth rates), and GH transgenic salmon pair fed a non-transgenic ration level (and thus growing at the non-transgenic rate) were examined for plasma hormone concentrations, and liver, muscle, hypothalamus, telencephalon, and pituitary mRNA levels. GH transgenic salmon exhibited increased plasma GH levels, and enhanced liver, muscle and hypothalamic GH mRNA levels. Insulin-like growth factor-I (IGF-I) in plasma, and growth hormone receptor (GHR) and IGF-I mRNA levels in liver and muscle, were higher in fully fed transgenic than non-transgenic fish. GHR mRNA levels in transgenic fish were unaffected by ration-restriction, whereas plasma GH was increased and plasma IGF-I and liver IGF-I mRNA were decreased to wild-type levels. These data reveal that strong nutritional modulation of IGF-I production remains even in the presence of constitutive ectopic GH expression in these transgenic fish. Liver GHR membrane protein levels were not different from controls, whereas, in muscle, GHR levels were elevated approximately 5-fold in transgenic fish. Paracrine stimulation of IGF-I by ectopic GH production in non-pituitary tissues is suggested by increased basal cartilage sulphation observed in the transgenic salmon. Levels of mRNA for growth hormone-releasing hormone (GHRH) and cholecystokinin (CCK) did not differ between groups. Despite its role in appetite stimulation, neuropeptide Y (NPY) mRNA was not found to be elevated in transgenic groups.

Denitrification potential in stream sediments impacted by acid mine drainage: effects of pH, various electron donors, and iron

Acid mine drainage (AMD) contaminates thousands of kilometers of stream in the western United States. At the same time, nitrogen loading to many mountain watersheds is increasing because of atmospheric deposition of nitrate and increased human use. Relatively little is known about nitrogen cycling in acidic, heavy-metal-laden streams; however, it has been reported that one key process, denitrification, is inhibited under low pH conditions. The objective of this research was to investigate the capacity for denitrification in acidified streams. Denitrification potential was assessed in sediments from several Colorado AMD-impacted streams, ranging from pH 2.60 to 4.54, using microcosm incubations with fresh sediment. Added nitrate was immediately reduced to nitrogen gas without a lag period, indicating that denitrification enzymes were expressed and functional in these systems. First-order denitrification potential rate constants varied from 0.046 to 2.964 day(-1). The pH of the microcosm water increased between 0.23 and 1.49 pH units during denitrification. Additional microcosm studies were conducted to examine the effects of initial pH, various electron donors, and iron (added as ferrous and ferric iron). Decreasing initial pH decreased denitrification; however, increasing pH had little effect on denitrification rates. The addition of ferric and ferrous iron decreased observed denitrification potential rate constants. The addition of glucose and natural organic matter stimulated denitrification potential. The addition of hydrogen had little effect, however, and denitrification activity in the microcosms decreased after acetate addition. These results suggest that denitrification can occur in AMD streams, and if stimulated within the environment, denitrification might reduce acidity.

Aberrant monocyte prostaglandin synthase 2 (PGS2) expression in type 1 diabetes before and after disease onset

METHODS

We examined monocyte prostaglandin synthase 2 (PGS2/COX2) expression in individuals at risk for or with type 1 diabetes including: (i) 58 established type 1 and 2 diabetic patients; (ii) 34 autoantibody positive (AA+) children and adults; (iii) 164 infants and young children with insulin-dependent diabetes mellitus (IDDM) susceptibility human leukocyte antigen (HLA) alleles; and (iv) 37 healthy control individuals, over a 5-yr period.

RESULTS

Established type 1 diabetic patients (1 month to 30+ yr post-disease onset) had significantly higher PGS2 expression than healthy controls; by contrast, insulin-treated type 2 diabetic patients had significantly lower PGS2 expression than healthy controls. Longitudinal studies of AA+ subjects at risk for type 1 diabetes indicated that 73% (11/15) of individuals who developed this disease during the study period expressed high levels of PGS2 prior to or after onset. We also found high level PGS2 expression in genetically at-risk infants and young children that correlated with having a first-degree relative with type 1 diabetes, but not with age, gender, or HLA genotype. In this population, high level PGS2 expression coincided with or preceded autoantibody detection in 30% (3/10) of subjects.

CONCLUSIONS

These findings suggest that high level monocyte PGS2 expression, although subject to fluctuation, is present in at-risk subjects at an early age and is maintained during progression to and after type 1 diabetes onset.

Cerulenin mimics effects of leptin on metabolic rate, food intake, and body weight independent of the melanocortin system, but unlike leptin, cerulenin fails to block neuroendocrine effects of fasting

Cerulenin and a related compound, C75, have recently been reported to reduce food intake and body weight independent of leptin through a mechanism hypothesized, like leptin, to involve hypothalamic nutrition-sensitive neurons. To assess whether these inhibitors act through mechanisms similar to mechanisms engaged by leptin, ob/ob and Ay (agouti) mice, as well as fed and fasted wild-type mice, were treated with cerulenin. Like leptin, cerulenin reduced body weight and food intake and increased metabolic rate in ob/ob mice, and cerulenin produced the same effects in wild-type mice, whereas lithium chloride, at doses that produce conditioned taste aversion, reduced metabolic rate. However, in contrast to leptin, cerulenin did not prevent effects of fasting on plasma corticosterone or hypothalamic levels of neuropeptide Y, agouti-related peptide, pro-opiomelanocortin, or cocaine- and amphetamine-related peptide mRNA. Also, in contrast to leptin, cerulenin was highly effective to reduce body weight in Ay mice, in which obesity is caused by blockade of the melanocortin receptor. These data demonstrate that cerulenin produces metabolic effects similar to effects of leptin, but through mechanisms that are independent of, or down-stream from, both leptin and melanocortin receptors.

Selecting a sensitive bacteriophage assay for evaluation of a prototype water recycling system

A rapid, simple, and direct (RSD) assay of eluate from filter concentration was developed to enumerate low numbers of MS2 bacteriophage, used as a surrogate for enteric viruses, from samples collected from a prototype-sized water recycling system. The RSD assay utilized a 50-ml eluate volume in a modified single-layer assay, neutralizing eluate pH by buffered, double-strength agar. The RSD assay developed was simpler and minimized sample-handling steps compared with another published method. The RSD assay method showed greater sensitivity than the other published method for recovering phage from filter eluate while avoiding pH shifts, which can inactivate phage. Grant numbers: NAGW 2356.

Physicians' experiences with patients who transgress boundaries

BACKGROUND

Boundary violations have been discussed in the literature, but most studies report on physician transgressions of boundaries or sexual transgressions by patients. We studied the incidence of all types of boundary transgressions by patients and physicians' responses to these transgressions.

METHODS

We surveyed 1,000 members of the Society of General Internal Medicine (SGIM) for the number of patient transgressions of boundaries which had occurred in the previous year. Categories were created by the investigators based on the literature. Physicians picked the most important transgression, and then were asked about their response to the transgression and its effect on the patient-physician relationship. Attitudinal questions addressed the likelihood of discharging patients who transgressed boundaries. The impact of demographic variables on the incidence of transgressions was analyzed using analysis of variance.

RESULTS

Three hundred thirty (37.5%) randomly selected SGIM members responded to the survey. Almost three quarters of the respondents had patients who used their first name, while 43% encountered verbal abuse, 39% had patients who asked personal questions, 31% had patients who were overly affectionate, and 27% encountered patients who attempted to socialize. All other transgressions, including physical abuse and attempts at sexual contact, were uncommon. Only gender affected the incidence of transgressions; female physicians encountered more personal questions (P = .001), inappropriate affection (P < .005), and sexually explicit language (P < .05) than male physicians and responded more negatively to boundary transgressions. Respondents dealt with transgressions by discussion with the patient or colleagues or by ignoring the incident, but such transgressions generally had a negative impact on the relationship. Most physicians would discharge patients who engaged in physical abuse or attempts at sexual contact, but were more tolerant of verbal abuse and overly affectionate patients.

CONCLUSIONS

Boundary transgressions by patients is common, but usually involves more minor infractions. Female physicians are more likely to encounter certain types of transgressions. The incidence and outcomes of such transgressions are important in assisting physicians to deal effectively with this issue.

Adrenalectomy reverses obese phenotype and restores hypothalamic melanocortin tone in leptin-deficient ob/ob mice

In genetically obese leptin-deficient ob/ob mice, adrenalectomy reverses or attenuates the obese phenotype. Relative to lean controls, ob/ob mice also exhibit decreased hypothalamic proopiomelanocortin (POMC) mRNA and increased hypothalamic agouti-related peptide (AGRP) mRNA and neuropeptide Y (NPY) mRNA. It has been hypothesized that this profile of hypothalamic gene expression contributes to the obese phenotype caused by leptin deficiency. To assess if reversal of obese phenotype by adrenalectomy entails normalization of hypothalamic gene expression, male wild-type and ob/ob mice were adrenalectomized (with saline supplementation) or sham adrenalectomized at 2 months of age. Mice were sacrificed 2 weeks after adrenalectomy, during which time food intake and body weight were monitored daily. After sacrifice, hypothalamic gene expression was assessed by Northern blot analysis as well as in situ hybridization. In wild-type mice, adrenalectomy significantly decreased AGRP mRNA but did not significantly influence POMC or NPY mRNA. In ob/ob mice, adrenalectomy reduced the levels of plasma glucose, serum insulin and corticosterone, and food intake toward or below wild-type levels, and it restored hypothalamic POMC and AGRP mRNA but not NPY mRNA to wild-type levels. These studies suggest that adrenalectomy reverses or attenuates the obese phenotype in ob/ob mice, in part by restoring hypothalamic melanocortin tone toward wild-type levels. These studies also demonstrate that factors other than leptin may play a major role in regulating hypothalamic melanocortin function.

Development and application of small-subunit rRNA probes for assessment of selected Thiobacillus species and members of the genus Acidiphilium

Culture-dependent studies have implicated sulfur-oxidizing bacteria as the causative agents of acid mine drainage and concrete corrosion in sewers. Thiobacillus species are considered the major representatives of the acid-producing bacteria in these environments. Small-subunit rRNA genes from all of the Thiobacillus and Acidiphilium species catalogued by the Ribosomal Database Project were identified and used to design oligonucleotide DNA probes. Two oligonucleotide probes were synthesized to complement variable regions of 16S rRNA in the following acidophilic bacteria: Thiobacillus ferrooxidans and T. thiooxidans (probe Thio820) and members of the genus Acidiphilium (probe Acdp821). Using (32)P radiolabels, probe specificity was characterized by hybridization dissociation temperature (T(d)) with membrane-immobilized RNA extracted from a suite of 21 strains representing three groups of bacteria. Fluorochrome-conjugated probes were evaluated for use with fluorescent in situ hybridization (FISH) at the experimentally determined T(d)s. FISH was used to identify and enumerate bacteria in laboratory reactors and environmental samples. Probing of laboratory reactors inoculated with a mixed culture of acidophilic bacteria validated the ability of the oligonucleotide probes to track specific cell numbers with time. Additionally, probing of sediments from an active acid mine drainage site in Colorado demonstrated the ability to identify numbers of active bacteria in natural environments that contain high concentrations of metals, associated precipitates, and other mineral debris.

Blood glucose monitoring skills in children with Type I diabetes

While blood glucose monitoring has become increasingly important in diabetes care, studies have yet to address the accuracy of youngsters' performance of blood glucose testing with current reflectance meters. The present study examined testing skills and predictors of accurate testing skills in a sample of 7-14-year-old children attending a summer camp for youth with diabetes (n=266). A 15-item behavior observational skill test was used to assess accuracy of blood glucose monitoring skills with reflectance meters. Accurate performance of individual skills ranged between 14.6% and 99.6% for the sample. However, a number of children made critical errors (errors that were likely to lead to inaccurate blood glucose testing results). When duration of diabetes and metabolic control were controlled, female gender, older age, experience with a particular meter, and absence of hypoglycemia at the time of testing were positively associated with accurate skill performance. Findings suggest that younger children, children using a new blood glucose testing meter, and children suspected of having hypoglycemia should be supervised and observed when testing. Although all young children should be supervised when blood glucose testing, boys may need closer supervision until an older age than girls. This study underscores the need for health care providers to periodically observe children's blood glucose monitoring techniques to assure accurate testing habits and to correct problematic testing behaviors.

Alkaline phosphatase knock-out mice recapitulate the metabolic and skeletal defects of infantile hypophosphatasia

Hypophosphatasia is an inborn error of metabolism characterized by deficient activity of the tissue-nonspecific isoenzyme of alkaline phosphatase (TNSALP) and skeletal disease due to impaired mineralization of cartilage and bone matrix. We investigated two independently generated TNSALP gene knock-out mouse strains as potential models for hypophosphatasia. Homozygous mice (-/-) had < 1% of wild-type plasma TNSALP activity; heterozygotes had the predicted mean of approximately 50%. Phosphoethanolamine, inorganic pyrophosphate, and pyridoxal 5'-phosphate are putative natural substrates for TNSALP and all were increased endogenously in the knock-out mice. Skeletal disease first appeared radiographically at approximately 10 days of age and featured worsening rachitic changes, osteopenia, and fracture. Histologic studies revealed developmental arrest of chondrocyte differentiation in epiphyses and in growth plates with diminished or absent hypertrophic zones. Progressive osteoidosis from defective skeletal matrix mineralization was noted but not associated with features of secondary hyperparathyroidism. Plasma and urine calcium and phosphate levels were unremarkable. Our findings demonstrate that TNSALP knock-out mice are a good model for the infantile form of hypophosphatasia and provide compelling evidence for an important role for TNSALP in postnatal development and mineralization of the murine skeleton.

Fasting regulates hypothalamic neuropeptide Y, agouti-related peptide, and proopiomelanocortin in diabetic mice independent of changes in leptin or insulin

Fasting increases hypothalamic neuropeptide Y (NPY) and agouti-related peptide (AGRP) messenger RNA (mRNA) and reduces hypothalamic POMC mRNA, and is also characterized by a reduction in plasma leptin, insulin, and glucose, each of which has been implicated in the regulation of hypothalamic gene expression. To further evaluate the roles of leptin, insulin, and glucose in mediating effects of fasting, we examined hypothalamic gene expression in nondiabetic and streptozotocin (STZ)-induced diabetic mice both under ad lib fed and 48-h fasted conditions. In both diabetic and nondiabetic mice, fasting stimulated hypothalamic NPY and AGRP mRNA and inhibited hypothalamic POMC mRNA and adipose leptin mRNA. However, in diabetic mice fasting had no effect on plasma leptin and insulin while decreasing plasma glucose, whereas in nondiabetic mice fasting decreased plasma leptin, insulin, and glucose. Furthermore, in nondiabetic fasted mice, NPY and AGRP mRNA were higher, and POMC mRNA and plasma glucose were lower, than in diabetic ad lib fed mice, even though insulin and leptin were similar in these two groups. These data are consistent with the hypothesis that although leptin and insulin regulate hypothalamic gene expression, glucose or other factors may have independent effects on hypothalamic and adipose gene expression under conditions of low insulin and leptin.

Only multiple autoantibodies to islet cells (ICA), insulin, GAD65, IA-2 and IA-2beta predict immune-mediated (Type 1) diabetes in relatives

We report here our prospective study of 15,224 non-diabetic, first-degree relatives of probands with immune-mediated (type 1) diabetes (IMD), of which 135 were found to eventually develop diabetes. We determined islet cell, insulin, GAD65, insulinoma-associated antigen-2 and 2beta autoantibodies (ICA, IAA, GAD65A, IA-2A and IA-2betaA), on the first available serum samples. The latter three autoantibodies were however assayed on subsets of the relatives with and without ICA, IAA and/or GAD65A, plus most of the relatives who developed diabetes. Of the relatives who progressed to diabetes, 94% had at least one of these autoantibodies on the first screening, while ICA proved to be the most sensitive single marker (sensitivity 74%). Risk of diabetes was however negligible when ICA was found in the absence of the others (5-year risk=5.3%), but increased dramatically whenever two or more autoantibodies were present (5-year risk=28.2% and 66.2%, respectively). The most predictive combination of markers was ICA plus IA-2A and/or IA-2beta A. Loss of first phase insulin release to IVGTT also occurred only in those ICA-positive relatives who had one or more of the other autoantibodies. The data suggests that significant beta-cell damage is seen only when the underlying autoimmunity has spread to multiple antigenic islet cell determinants. Combinations of the autoantibodies occurred most often in relatives with the highest risk HLA-DR/DQ phenotypes. These data document that only relatives positive for at least two or more of these five autoantibodies are at significant risk of diabetes themselves. Intervention trials for the prevention of type 1 diabetes could be designed based on testing for these autoantibodies alone, without the need for HLA typing and IVGTT testing.

Web-based segmentation and display of three-dimensional radiologic image data

In many clinical circumstances, viewing sequential radiological image data as three-dimensional models is proving beneficial. However, designing customized computer-generated radiological models is beyond the scope of most physicians, due to specialized hardware and software requirements. We have created a simple method for Internet users to remotely construct and locally display three-dimensional radiological models using only a standard web browser. Rapid model construction is achieved by distributing the hardware intensive steps to a remote server. Once created, the model is automatically displayed on the requesting browser and is accessible to multiple geographically distributed users. Implementation of our server software on large scale systems could be of great service to the worldwide medical community.

Incidence of percutaneous injuries at a dental school: a 4-year retrospective study

BACKGROUND

Infection control training for predoctoral dental students, dental hygiene students, and dental assistant students has assumed an important role in the educational process at our institution. As part of an ongoing review of the curriculum at our school, we conducted a retrospective analysis of reported percutaneous injuries during the years 1991 through 1994 to determine whether the increase in infection control training introduced at the school in 1990 has had an effect on our rate of percutaneous injuries.

METHODS

The population examined in this retrospective study consisted of predoctoral and postdoctoral dental students, dental hygiene students, dental assistant students, and staff. The data for this retrospective study were obtained from annual reports of occupational exposures incurred by students and staff. These annual reports were generated by compiling and summarizing all percutaneous injury incident reports that were prepared for that year.

RESULTS

Our results indicate, that except for an increase in 1992, the total number and incidence of reported percutaneous injuries decreased from 1991 to 1994. Statistically significant decreases were seen in the total number of reported percutaneous injuries for all students, staff, and all groups combined. On the basis of data available for 1993 and 1994, the incidence of reported percutaneous injuries per 1000 procedures was fairly constant over these 2 years. Distribution of percutaneous injuries by source varied during the 4-year period.

CONCLUSIONS

As part of the outcomes assessment program at our institution, we conducted a retrospective study of reported percutaneous injuries from 1991 to 1994. This study demonstrated that, although the total number of injuries decreased significantly, the rates within certain individual groups remained unchanged. On the basis of this observation, increased emphasis in the prevention of percutaneous injuries through additional training is indicated for these groups.

Effect of microgravity on Escherichia coli and MS-2 bacteriophage disinfection by iodinated resins

Experiments on chemical disinfection by iodinated resins were conducted on STS 50 (USML-1), which flew a 13 day mission during 1992. Fluid processing apparatus containing microorganisms and iodinated resins was assembled in either Manhattan, Kansas, or Boulder, Colorado, and loaded on-board the Space Shuttle for the mission. Pentaiodide resin was more effective than the triiodide resin against Escherichia coli. Both resins were more effective bactericides at unit gravity than microgravity because of cosedimentation of bacteria and iodinated resin beads. In bacteriophage experiments, the triiodide resin reduced the viable titer of MS-2 by nine logs. The few viable phage surviving chemical disinfection were associated with precipitant formation in the fluid processing apparatus.

Although DR3-DQB1*0201 may be associated with multiple component diseases of the autoimmune polyglandular syndromes, the human leukocyte antigen DR4-DQB1*0302 haplotype is implicated only in beta-cell autoimmunity

Human leukocyte antigen (HLA)-DRB1 and -DQB1 alleles were analyzed using a PCR-based sequence-specific priming technique in 16 patients with autoimmune polyglandular syndrome type I (APS-I), 31 patients with APS-II, and 110 patients with component diseases of APS-II, including 9 patients with isolated Addison's disease, 43 patients with Hashimoto's thyroiditis, 22 patients with Graves' disease, and 36 patients with vitiligo. No significant associations was observed between HLA and APS-I patients in our data set, nor was sharing of HLA haplotypes by sibling pairs affected by APS I significantly different from the random expectation. Thus, HLA-DRB1 and -DQB1 genes are probably not involved in APS-I. To delineate the associations between HLA-DRB1, DQB1, and APS-II, we analyzed APS-II patients with or without beta-cell autoimmunity [i.e. insulin-dependent diabetes (IDD) and/or islet cell or glutamic acid decarboxylase autoantibodies]. Our results suggest that the association between DR4-DQB1*0302 and APS-II was entirely due to the presence of pancreatic beta-cell autoimmunity, since this haplotype was otherwise not significantly associated with APS-II or with any other of its component diseases. In contrast, the DR3-DQB1*0201 haplotype was associated not only with IDD, but also with APS-II in the absence of pancreatic beta-cell autoimmunity, as were several its component diseases, including isolated Addison's disease, Graves' disease, and Hashimoto's thyroiditis. Interestingly, the frequency of DQB1*0602, a dominantly protective allele against IDD, was not significantly decreased in the APS-II patients with IDD or beta-cell autoimmunity, albeit the patient numbers were small. This phenomenon may suggest that the development of autoimmunity to nonpancreatic endocrine glands may predispose autoimmunity to the pancreatic beta-cells and involve genes other than those of the MHC.

Association of anophthalmia and esophageal atresia

We report on a boy and a girl with bilateral anophthalmia and proximal esophageal atresia. In addition to vestigial optic nerves and chiasma, MRI studies showed other central nervous system abnormalities; one had ectopic tissue in the hypothalamic region, and the other hand generalized ventriculomegaly associated with atrophy. Two other cases, both males, have been reported with anophthalmia and esophageal atresia as their only malformations. These 4 cases are reviewed in light of recent advances in the understanding of ocular embryogenesis and of the midbrain as a development field. Concurrence of these defects appears to be non-random.

A 15-year review of esophagectomy for carcinoma of the esophagus and cardia

OBJECTIVE

To evaluate the effect of surgical approach and adjuvant therapy on patients with carcinoma of the esophagus and/or cardia.

DESIGN

Retrospective analysis of 157 consecutive patients who underwent esophagectomy.

SETTING

A private university medical center and its affiliated community hospital.

PATIENTS

One hundred twenty men and 37 women (mean age, 61.7 years) with carcinoma of the esophagus and/or cardia that was surgically treated between 1978 and 1993.

INTERVENTIONS

Three approaches were used for resection: Transhiatal esophagectomy (THE) (n = 67), transthoracic esophagectomy (TTE) (n = 71), and abdominal-only esophagectomy (AOE) (n = 19). Sixty-five patients received adjuvant radiotherapy and chemotherapy.

MAIN OUTCOME MEASURES

Surgical mortality, morbidity, and survival and the effect of adjuvant therapy.

RESULTS

The overall surgical mortality rate was 7.6%: 12.7% with the TTE, 4.5% with the THE, and 0% with the AOE approach. A significantly increased incidence of adult respiratory distress syndrome (P < .001) and empyema (P < .001) was seen with the TTE approach. The average intraoperative blood loss (P = .08) and the median intensive care unit stay (P = .26) and hospital stay (P = .40) were decreased with the THE and AOE approaches when compared with the TTE approach without significance. The overall median survival time was 17 months, with a 5-year survival rate of 21%. There was no significant difference in survival by pathologic stage between approaches. The addition of adjuvant therapy did not affect the overall median survival time or the 5-year survival rate. Node-positive patients did benefit from adjuvant radiotherapy and chemotherapy, with increased median survival times from 7 to 15 months and a 5-year survival rate from 0% to 15% (P = .01).

CONCLUSIONS

The THE and AOE approaches have fewer early complications than does TTE. Both THE and TTE have equal long-term survival rates. Adjuvant therapy provides increased survival to node-positive patients with carcinoma of the esophagus and/or cardia.

Islet cell antibodies predict insulin-dependent diabetes in United States school age children as powerfully as in unaffected relatives

Islet cell antibodies (ICA) in the sera of nondiabetic relatives of patients with insulin-dependent diabetes (IDD) are predictive of the disease, a finding that permits the design of intervention strategies to prevent it. However, 85% or more of patients with new onset IDD have no affected relative. We therefore screened 9,696 schoolchildren between the ages of 5 and 18 yr (mean age 10.7 yr) in Pasco County, Florida for ICA in three surveys during 1984/5, 1987/8, and 1990/1 and have followed them prospectively. Approximately 4,000 of these children have been followed for nearly 8 yr. ICA titers > or = 10 Juvenile Diabetes Foundation units on replicate tests were detected in 57 of the children (0.59%). 10 children have developed diabetes so far, and all had ICA detected beforehand. The likelihood of developing IDD among the ICA-positive children was compared with 2,959 age-matched nondiabetic first degree relatives of IDD probands who were screened for ICA by our laboratory during the same time period and also followed prospectively. Of 103 (3.5%) ICA-positive relatives, 31 have developed IDD. Life table analysis reveals no statistically significant differences in the probability of developing IDD between the ICA-positive schoolchildren and ICA-positive first degree relatives (P = 0.3). The estimated risk of developing IDD by 7 yr in the ICA-positive schoolchildren was 45% (95% confidence interval 15-74%) compared with 43% (confidence interval 22-63%) in the relatives. We conclude that ICA appear to be as predictive of IDD in low-risk schoolchildren as they are in high-risk relatives. These data suggest that it is feasible to predict IDD by screening a general population of schoolchildren for ICA and that those found to be positive could be considered, in addition to relatives, for intervention protocols to prevent the disease.

A comparison of growth rates of acoustic neuromas: nonsurgical patients vs. subtotal resection

A conservative approach to the management of acoustic neuromas in elderly patients has been used since 1971. Elderly patients without symptoms of brain stem compression are initially treated by observation and yearly radiographic imaging. A translabyrinthine radical-subtotal resection is performed if brain stem compression is present or if tumor is growing rapidly. Twenty-three patients, ages 65 to 86 years, had initial nonsurgical management of their tumors. Growth rates could be determined for 16 patients. Thirteen patients not requiring surgery had an average tumor growth rate of 0.6 mm/yr. Three patients with an average growth rate of 6.8 mm/yr eventually required surgery. No patient whose tumor was < 15 mm at initial evaluation has experienced brain stem symptoms or demonstrated rapid tumor growth. Twenty-four patients ages 65 to 86 years underwent planned subtotal tumor excision. Eighteen patients followed postoperatively for more than 1 year demonstrated an average rate of regrowth of tumor of 0.7 mm/yr.

Middle ear air injection after chronic ear surgery

In the early period after chronic ear surgery, the reasons for conductive hearing loss may be difficult to determine. Patients who cannot autoinflate the middle ear after 3 weeks, or who have a negative Rinne test result with the 512 Hz tuning fork, are treated with a transtympanic injection of 0.5 cc of air with a 27-gauge needle and tuberculin syringe. This represents 20% of patients who had chronic ear surgery. Results show that hearing may be immediately improved, the sensation of pressure in the ear may be reduced, and fluid may be cleared from the middle ear. Other benefits may include the release of adhesions. The surgeon is better able to assess the thickness of the graft, and the status of the ossicular chain reconstruction can be determined. There have been no complications of middle ear infection or failure of the micropuncture site to heal. In our practice, middle ear air injection is a routine procedure in patients with inadequate eustachian tube function after chronic ear surgery. This report describes the results of 100 patients over 14 years who received middle ear air injections after chronic ear surgery compared with a control group of 100 patients who did not meet the criteria for requiring air injection. Hearing was immediately improved in 74% of patients as determined by Rinne testing. Audiograms were performed in 25 of these patients, documenting a mean improvement in pure-tone average of 16 dB. The long-term hearing results in patients undergoing air injection, who by definition had evidence of poor eustachian tube function, are similar to the results in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

The death of a child with diabetes from neglect. A case study

This case report of a child with insulin-dependent diabetes mellitus (IDDM) describes a naturally occurring ABABCA design. The A condition represents poor diabetes management provided in the home setting, and the B and C conditions represent improved diabetes management in residential treatment (condition B) or foster care (condition C). The A condition was consistently associated with episodes of diabetic ketoacidosis, high glycosylated hemoglobin percentage, and school failure. In contrast, the B/C conditions were consistently associated with improved health status and school performance. On two occasions, the child was returned to condition A by the state's protective service agency (HRS) in direct conflict with the recommendations of the child's psychological and medical treatment staff. During her last condition A placement, the youngster died. Chronically ill children who are neglected may not receive the protection they need because of lack of awareness about the psychosomatic aspects of their problem.

Interactions of bacteria and microflagellates in sequencing batch reactors exhibiting enhanced mineralization of toxic organic chemicals

Community level interactions were studied in non-axenic sequencing batch reactors (SBRs) being used to treat 2,4-dinitrophenol (DNP). Increasing the influent DNP concentrations from 1 to 10 µg ml(-1) eliminated large predatory organisms such as rotifers and ciliated protozoa from the SBRs. Under steady-state conditions at a DNP concentration of 10 µg ml(-1), supplemental additions of glucose enhanced DNP degradation and led to the establishment of a microbial community consisting of five species of bacteria and a variety of microflagellates. The bacteria and flagellates exhibited oscillating population dynamics in this system, possibly indicating predator-prey interactions between these two groups. Only two of the five bacteria isolated from this system could utilize glucose as a growth substrate, and one of these two species was the only organism that could mineralize DNP in the system. The other three bacteria could grow using metabolic by-products of one of the glucose-utilizing strains (Bacillus cereus) found in the reactors. Supplemental glucose additions increased the average size of bacterial floc particles to 172 µm, compared with 41 µm in SBRs not receiving glucose. It is theorized that the enhanced mineralization of DNP in this non-axenic system was attributable to increased community interactions resulting in increased bacterial flocculation in SBRs receiving supplemental glucose additions.

Behavioral treatment of nocturnal enuresis in children with insulin-dependent diabetes mellitus

Examined whether a well-established treatment program for functional enuresis, the urine alarm procedure, would be useful for children with both enuresis and diabetes. 5 children between the ages of 7 and 14 whose pretreatment physical examination suggested no neurological impairment were treated. A multiple baseline design across children indicated that the urine alarm procedure was successful in stopping enuretic episodes for all 5 children with treatment gains maintained for the 4 children available for assessment at 2-month follow-up. These results suggest that if no diabetes-related organic impairment is evident, behavioral treatment for enuresis can be beneficial for children with diabetes.

Insulin dependent diabetes 1991

Insulin dependent diabetes (IDD) most often results from the autoimmune destruction of pancreatic beta cells. During this process, autoantibodies to islet cell constituents (islet cell cytoplasm, 64KDa protein [GAD]) and to insulin arise and can be used for disease prediction if found before onset or for classification at onset in cases in which type of diabetes is not clear. Approximately 4-5% of immediate family members have at least one of these antibodies. The younger the age and the higher the antibody titer, the greater the chance of IDD developing. Because studies using immunosuppression in newly-diagnosed IDD have shown transient prolongation of beta cell function, efforts to use such therapies prior to diabetes onset may prevent beta cell destruction and clinical disease. A multicenter trial is underway in Florida to screen relatives for diabetes-related antibodies and then to enter those found positive and at increased risk in a study to prevent diabetes. Details of the study and its rationale are presented.

Effects of prenatal alcohol exposure at school age. II. Attention and behavior

Alcohol, a potent teratogen, has been suggested as an etiologic agent in attention deficit disorder with hyperactivity (ADHD), which is often diagnosed in children with fetal alcohol syndrome (FAS) and in children of alcoholics. We studied attentional and behavioral factors associated with diagnosis of this disorder in children selected from a predominantly low-income, black population who were tested as part of a longitudinal follow-up of children with prenatal alcohol exposure. Sixty-eight children with a mean age of 5 years 10 months, born to three groups of mothers, were assessed. These groups consisted of: a) women who reported not drinking during pregnancy (n = 21), b) women who reported drinking throughout pregnancy (n = 25), and c) women who reported drinking an equivalent amount but who stopped drinking after educational intervention during the second trimester (n = 22). Dimensions assessed included factors related to attention on a computerized task, impulsivity, and the presence of psychiatrically significant internalizing and externalizing behaviors. In addition, free play and mother-child interactions were video-taped, and evidence of overactive and noncompliant behaviors were noted. Hyperactivity and impulsive behavior were not evident. Results indicated that children exposed throughout pregnancy showed deficits in the ability to sustain attention and were more often described by teachers, although not by their mothers, as showing attentional and behavioral problems. Problems in both internalizing and externalizing behaviors also were noted by teachers. However, when current drinking was controlled, only externalizing behaviors remained different by group.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessing daily management of childhood diabetes using 24-hour recall interviews: Reliability and stability

Conducted 24-hr recall interviews concerning daily diabetes management with seventy-eight 6- to 19-year-old patients and their parents. Patients and parents were interviewed independently nine times over 3 months. Data obtained were used to construct 13 adherence measures. All measures yielded statistically significant estimates of parent-child concordance. Parent-child agreement was higher for weekday versus weekend behaviors and when based on nine versus three interviews. For the sample as a whole, parent-child concordance remained stable over the course of the study. Compared to the older patients, the 6- to 9-year-olds exhibited poorer parent-child agreement on measures involving time (e.g., injection and exercise-duration measures). This deficit disappeared, however, as the children became more practiced with the interview procedure. The dietary and glucose-testing measures exhibited moderate stability over the 3-month study. Lower stability estimates were obtained for the exercise and injection measures.

Central nervous system toxicity from nebulized atropine sulfate

Central anticholinergic intoxication can result from iatrogenic sources. We report the occurrence of a central anticholinergic syndrome in a patient treated with aerosolized atropine.

Assessing daily diabetes management by 24-hour recall interview: the validity of children's reports

The current investigation examined the accuracy of diabetic children's 24-hr recall data by comparing the 7- to 12-year-old children's reports to direct observations of their behavior. Observers' data evidenced sufficient reliability to serve as an acceptable standard to which the children's 24-hr recall data could be compared. The children exhibited excellent agreement with the observers' data on all measures of the occurrence/nonoccurrence of events, including insulin injections, exercise periods, glucose tests, meal, type and amount of insulin injected. Although somewhat poorer reporters on some behaviors, differences were small. Children underreported most dietary behaviors and some exercise behaviors.

Supplemental Substrate Enhancement of 2,4-Dinitrophenol Mineralization by a Bacterial Consortium

A Janthinobacterium sp. and an actinomycete, both capable of mineralizing 2,4-dinitrophenol (DNP), were used to construct a consortium to mineralize DNP in nonaxenic bench-scale sequencing batch reactors (SBRs). Average K m values for DNP mineralization by pure cultures of the Janthinobacterium sp. and the actinomycete were 0.01 and 0.13 μg/ml, respectively, and the average maximum specific growth rate (μ max ) values for them were 0.06 and 0.23/h, respectively. In the presence of NH 4 Cl, nitrite accumulation in pure culture experiments and in the SBRs was stoichiometric to initial DNP concentration and the addition of nitrogen enhanced DNP mineralization in the SBRs. Mineralization of 10 μg of DNP per ml was further enhanced in SBRs by the addition of glucose at concentrations of 100 and 500 μg/ml but not at 10 μg/ml. Possible mechanisms for this enhanced DNP mineralization in SBRs were suggested by kinetic analyses and biomass measurements. Average μ max values for DNP mineralization in the presence of 0, 10, 100, and 500 μg of glucose per ml were 0.33, 0.13, 0.42, and 0.59/h, respectively. In addition, there was greater standing biomass in reactors amended with glucose. At steady-state operation, all SBRs contained heterogeneous microbial communities but only one organism, an actinomycete, that was capable of mineralizing DNP. This research demonstrates the usefulness of supplemental substrates for enhancing the degradation of toxic chemicals in bioreactors that contain heterogeneous microbial communities.

Psychological and physiological responses to acute laboratory stressors in insulin-dependent diabetes mellitus adolescents and nondiabetic controls

Thirty 11- to 18-year old adolescents with insulin-dependent diabetes mellitus (IDDM) of at least 1-year duration and 15 nondiabetic controls were subjected to three laboratory stressors: a venipuncture and two public-speaking tasks. Half of the IDDM participants were in good metabolic control prior to the inception of the experiment and half were in poor control. The IDDM adolescents in poor control and the nondiabetics were matched to the well-controlled IDDM group on the basis of age, sex, and race. The two IDDM groups were also matched on disease duration. Self-report, behavioral, and physiological measures of anxiety or arousal were monitored during the stress.

The prodrome of bullous pemphigoid

Bullous pemphigoid is an autoimmune bullous dermatosis that can be preceded by a prodromal phase, usually lasting weeks to months, during which the cutaneous changes are dermatitic rather than bullous. Two cases of unusually long prodromal periods, 18 months and 6 years, are reported.

Immunosuppression with azathioprine and prednisone in recent-onset insulin-dependent diabetes mellitus

We randomly assigned 46 patients (mean age, 11.7 years; range, 4.5 to 32.8) with newly diagnosed insulin-dependent diabetes mellitus within two weeks of beginning insulin to receive either corticosteroids for 10 weeks plus daily azathioprine for one year or no immunosuppressive therapy. Half the 20 immunosuppressed patients completing the one-year trial had satisfactory metabolic outcomes (hemoglobin A1c less than 6.8 percent; stimulated peak C peptide greater than 0.5 nmol per liter; insulin dose less than 0.4 U per kilogram of body weight per day) as compared with only 15 percent of the controls. Three of 20 immunosuppressed patients, but no controls, were insulin independent at one year. Two of these continue to receive azathioprine without insulin after more than 27 months of follow-up. The response to immunosuppression correlated with older age, better initial metabolic status, and lymphopenia (less than 1800 lymphocytes per cubic millimeter) resulting from immunosuppression. The side effects of azathioprine included vomiting in one patient and mild hair loss in several others. Prednisone use resulted in a transient cushingoid appearance, weight gain, and hyperglycemia. The growth rate remained normal in all patients. We conclude that early immunosuppression with short-term use of corticosteroids plus daily azathioprine can improve metabolic control in some patients with insulin-dependent diabetes mellitus, but results from this unblinded study are preliminary and require further confirmation and long-term follow-up.

Inherited susceptibility to insulin-dependent diabetes is associated with HLA-DR1, while DR5 is protective

Of the HLA allelic associations with insulin-dependent diabetes (IDD) reported to date. DR3 and DR4 have been the most positive and DR2 the most negative. In 952 Caucasian proband patients reported here, only 57 or 6% had no DR3 or DR4 alleles. When these 57 patients were compared to 249 Caucasian controls similarly lacking DR3 and DR4 antigens, there were excesses of DR1 (P = 0.13) and DRW8 (P = 0.01) and deficiencies of DR2 (P = 0.03) and DR5 (P = 0.03) in the patient group. The most common phenotype in this group of patients was DR1/DR7 (12.3%). Only four DR-homozygous patients involving alleles other than DR3 and DR4 were found by genotyping, and all were DR1 homozygotes. Among 506 patients wuth DR3/DRX or DR4/DRX phenotypes, DR1 was more frequent (P = 0.001; Bonferronni P = 0.006), and DR2 (P = 0.001) and DR5 (P = 0.001) less frequent than 243 HLA-matched controls. Of 187 patients with a single DR3 and no DR4, DR1 was more frequent (P = 0.02), with DR2 (P = 0.001) and DR5 (P = 0.02) less frequent than 94 HLA DR-compatible controls. Among 319 patients with a single DR4 but no DR3, DR1 was again more frequent (P = 0.01) and DR2 (P = 0.001) and DR5 (P = 0.001) less frequent than 149 HLA-matched controls. We conclude that DR1 is an additional risk DR allele for IDD to that of DR3 and DR4, and DR5 an additional protective DR allele to that of DR2.

Diabetologists' judgments of diabetic control: reliability and mathematical simulation

In study 1, laboratory and supervised blood or urine test data from actual cases were used to develop patient profiles. Seven diabetologists from the same institution rated the diabetic control of 125 profiles on a four-point scale (1 = poor, 2 = fair, 3 = good, 4 = excellent). Six of the 7 diabetologists demonstrated adequate intra- and interrater reliability. Study 2 assessed the reliability of judgments of diabetic control made by diabetologists working in two different settings. There were 9 raters from institution 1 and 8 from institution 2. The impact of the amount and type of information on judgment reliability was evaluated by developing two types of profiles. The test form contained only laboratory and supervised blood or urine test data similar to that utilized in study 1. The history form contained this information as well as other descriptive data typically available to diabetologists. The 17 diabetologists rated 125 anonymous profiles on each of two separate occasions approximately 1 wk apart. On one occasion they rated profiles presented on the test form. On the other occasion they rated profiles presented on the history form. As in study 1, the diabetologist raters demonstrated adequate intra- and interrater reliability. Intrarater reliability was somewhat better when rating test form profiles compared with history form profiles. Reliability was not higher within than between institutions. An analysis of the relative contribution of different diabetes control indices to the diabetologists' judgments indicated that HbA1 influenced raters' judgments at both institutions more than any other single variable.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in insulin-like growth factors I and II and their binding protein after a single intramuscular injection of growth hormone

The concentrations of insulin-like growth factors I and II (IGF-I and IGF-II) and their binding proteins in serum were measured in 10 GH-deficient patients before and after a single 6-IU injection of GH. Serum IGF-I concentrations were initially low, increased significantly by 8 and 24 h, and decreased to pretreatment levels 48 and 72 h after GH administration. Serum IGF-II concentrations also were low initially and did not increase by 8 and 24 h, but were, however, significantly higher 48 and 72 h after GH administration. In GH-deficient patients before GH administration, binding of IGF-I or IGF-II to serum proteins was restricted primarily to proteins of 50K mol wt. Little or no binding to proteins of 150,000 mol wt was found. By 8 and 24 h after GH injection, IGF-I, but not IGF-II, bound primarily to a protein(s) of 150K mol wt, as in normal subjects. IGF-II remained bound to a 50K mol wt protein. By 48 and 72 h after administering GH, however, the binding pattern was reversed, and IGF-II, but not IGF-I, bound predominantly to a protein(s) of 150K mol wt. Our data demonstrate both a temporal dissociation in the responses of IGF-I and IGF-II to GH and a similar temporal dissociation in the binding of IGF-I and IGF-II to the large mol wt (150K) binding protein. This dissociation, particularly the latter, may provide a means for better characterization of protein fractions in binding IGF, particularly in terms of specificity.

Renal function in rats chronically exposed to high altitude

Chronic exposure of rats to a simulated altitude of 18,000 ft (5,500 m) results in severe polycythemia and consequent reduction of the plasma fraction. However, glomerular filtration rate is usually well maintained. This study was conducted to determine whether an increase in effective renal blood flow (ERBF) plays a role in maintaining a normal glomerular filtration rate in the chronically hypoxic rats. Various measurements of renal function were made in conscious trained and chronically catheterized animals. After exposure to high altitude for 30 days, hematocrit ranged from 64 to 77%. Despite this severe reduction in the plasma fraction, however, renal plasma flow decreased by only 25%, primarily owing to an increase in ERBF. The glomerular filtration rate was within the normal range. Since blood pressure remained unchanged, the increase in ERBF must have resulted from renal vasodilation. Acute removal of the hypoxic stimulus did not reverse the increased ERBF, suggesting that the vasodilation may have been of structural origin.