Single-stage nasal reconstruction with the islanded forehead flap

BACKGROUND AND PURPOSES

Multi-staged forehead flaps are a well-recognised reconstructive workhorse for subtotal and total nasal defects. It carries the disadvantage of repeated trips to theatre for revisional surgery, which is not suited to all patient cohorts. The single-stage islanded forehead flap eliminates this need. We detail our indications and outcomes of using this flap to highlight the maintained versatility of the technique without significant compromise on reconstructive and patient outcome.

SUBJECTS STUDIED AND METHODS

A prospective surgical database was collated where patients were categorised as partial or total reconstruction. We detail surgical technique and review of rationale of patient selection. Patient demographics, perioperative data and follow-up course were recorded.

MAIN FINDINGS

A total of 22 patients were recorded from both the U.K. and Ethiopia via working with the charity Facing Africa. Defects occurred from a mixture of trauma, Noma and cancer resections. Thirteen were total nasal reconstructions and nine partial. The mean follow-up period was 2.25 years. We experienced two major complications which required minor revision in the theatre and two minor complications, all resolved satisfactorily.

CONCLUSIONS

We demonstrate good outcomes and safety of the procedure in this first report of a varied cohort of nasal reconstructions in a heterogenous cohort of patients. We advocate the use of this flap in the multi-morbid patient where recovery can be expedited or those who have limitations from economical restraints.

Polar cod in jeopardy under the retreating Arctic sea ice

The Arctic amplification of global warming is causing the Arctic-Atlantic ice edge to retreat at unprecedented rates. Here we show how variability and change in sea ice cover in the Barents Sea, the largest shelf sea of the Arctic, affect the population dynamics of a keystone species of the ice-associated food web, the polar cod (Boreogadus saida). The data-driven biophysical model of polar cod early life stages assembled here predicts a strong mechanistic link between survival and variation in ice cover and temperature, suggesting imminent recruitment collapse should the observed ice-reduction and heating continue. Backtracking of drifting eggs and larvae from observations also demonstrates a northward retreat of one of two clearly defined spawning assemblages, possibly in response to warming. With annual to decadal ice-predictions under development the mechanistic physical-biological links presented here represent a powerful tool for making long-term predictions for the propagation of polar cod stocks.

Polar cod egg and larval drift patterns in the Svalbard archipelago

Spawning of polar cod (Boreogadus saida) in the vicinity of the Svalbard archipelago has not been directly observed. From the distribution pattern of polar cod 0-group observed during annual monitoring of the Barents Sea, it has, however, been inferred that spawning occurs in Svalbard waters most years. We wanted to investigate the possibility of back-tracking the larvae from these observed distribution areas to the spawning areas from which they originated and applied a coupled ocean–sea ice and particle tracking model to simulate the drift of particles released at suggested spawning sites. The model was run for 1 year (December 2006–September 2007), and the results were compared to observations of polar cod larvae in the autumns of 2007 and 2004–2010. The particles released in the western fjords were mostly retained in the fjords. For the rest of the suggested spawning grounds, the released particles drifted mostly clockwise around the archipelago. Model runs mainly indicated a drift pattern with end points that qualitatively match the main features of the August–September distribution of the polar cod 0-group observed. We conclude that the suggested spawning sites on the southern, northern and eastern sides of Svalbard could have caused a distribution of 0-group polar cod similar to that observed during August–September 2007. From the environmental factors experienced during drift of eggs and larvae and assumptions about habitat suitability for survival and growth, we conclude that spawning in the Svalbard area probably occurs on the southern and eastern sides and later than the area in the southeastern Barents Sea.

Predictive Value of ICD-9-CM Codes Used in Vaccine Safety Research

Objectives: To assess how well selected ICD-9-CM diagnosis codes predict adverse events; to model bias and power loss when vaccine safety analyses rely on unverified codes.

Methods: We extracted chart verification data for ICD-9-CM diagnosis codes from six Vaccine Safety Datalink (VSD) publications and modeled biases and power losses using positive predictive value (PPV) estimates and ranges of code sensitivity.

Results: Positive predictive values were high for type 1 diabetes (80%) in children, relative to WHO criteria, and intussusception (81%) in young children, relative to a standard published case definition. PPVs were moderate (65%) for inpatient and emergency department childhood seizures and low (21%) for outpatient childhood seizures, both relative to physician investigator judgment. Codes for incident central nervous system demyelinating disease in adults had high PPV for inpatient codes (80%) and low PPV for outpatient codes (42%) relative to physicians’ diagnoses. Modeled biases were modest, but large increases in frequencies of adverse events are required to achieve adequate power if unverified ICD-9-CM codes are used, especially when vaccine associations are weak.

Conclusions: ICD-9-CM codes for type 1 diabetes in children, intussusception in young children, childhood seizures in inpatient and emergency care settings, and inpatient demyelinating disease in adults were sufficiently predictive for vaccine safety analyses to rely on unverified diagnosis codes. Adverse event misclassification should be accounted for in statistical power calculations.

Prophylactic Swallowing Exercises in Head and Neck Cancer Radiotherapy

Many head and neck cancer (HNC) survivors experience reduced quality of life due to radiotherapy (RT)-related dysphagia. The aim of this prospective randomized trial was to evaluate the impact of prophylactic swallowing exercises on swallowing-related outcomes in HNC patients treated with curative RT. Patients treated with primary RT for HNC were candidates for this randomized protocol. Participants in the exercise group were instructed to perform swallowing exercises at home. Participants in the control group were given standard care. Patients were evaluated with modified barium swallow and several other secondary outcome measures at four and nine different time points, respectively. Data were analyzed according to intention-to-treat analyses. A total of 44 consecutive patients were included; 22 in each group. In general, there was no difference between the two groups regarding any of the dysphagia outcomes during and after treatment. Adherence to exercises was poor and dropouts due to especially fatigue were very frequent in both groups. Systematic swallowing exercises had no impact on swallowing outcomes within the first year after RT. Despite repeated supervised sessions, adherence to exercises was a major issue and dropouts were frequent in both the intervention and control group.

Real-time ichthyoplankton drift in Northeast Arctic cod and Norwegian spring-spawning herring

Background

Individual-based biophysical larval models, initialized and parameterized by observations, enable numerical investigations of various factors regulating survival of young fish until they recruit into the adult population. Exponentially decreasing numbers in Northeast Arctic cod and Norwegian Spring Spawning herring early changes emphasizes the importance of early life history, when ichthyoplankton exhibit pelagic free drift. However, while most studies are concerned with past recruitment variability it is also important to establish real-time predictions of ichthyoplankton distributions due to the increasing human activity in fish habitats and the need for distribution predictions that could potentially improve field coverage of ichthyoplankton.

Methodology/Principal Findings

A system has been developed for operational simulation of ichthyoplankton distributions. We have coupled a two-day ocean forecasts from the Norwegian Meteorological Institute with an individual-based ichthyoplankton model for Northeast Arctic cod and Norwegian Spring Spawning herring producing daily updated maps of ichthyoplankton distributions. Recent years observed spawning distribution and intensity have been used as input to the model system. The system has been running in an operational mode since 2008. Surveys are expensive and distributions of early stages are therefore only covered once or twice a year. Comparison between model and observations are therefore limited in time. However, the observed and simulated distributions of juvenile fish tend to agree well during early fall. Area-overlap between modeled and observed juveniles September 1^st range from 61 to 73%, and 61 to 71% when weighted by concentrations.

Conclusions/Significance

The model system may be used to evaluate the design of ongoing surveys, to quantify the overlap with harmful substances in the ocean after accidental spills, as well as management planning of particular risky operations at sea. The modeled distributions are already utilized during research surveys to estimate coverage success of sampled biota and immediately after spills from ships at sea.

Predictive value of ICD-9-CM codes used in vaccine safety research

OBJECTIVES

To assess how well selected ICD-9-CM diagnosis codes predict adverse events; to model bias and power loss when vaccine safety analyses rely on unverified codes.

METHODS

We extracted chart verification data for ICD-9-CM diagnosis codes from six Vaccine Safety Datalink (VSD) publications and modeled biases and power losses using positive predictive value (PPV) estimates and ranges of code sensitivity.

RESULTS

Positive predictive values were high for type 1 diabetes (80%) in children, relative to WHO criteria, and intussusception (81%) in young children, relative to a standard published case definition. PPVs were moderate (65%) for inpatient and emergency department childhood seizures and low (21%) for outpatient childhood seizures, both relative to physician investigator judgment. Codes for incident central nervous system demyelinating disease in adults had high PPV for inpatient codes (80%) and low PPV for outpatient codes (42%) relative to physicians' diagnoses. Modeled biases were modest, but large increases in frequencies of adverse events are required to achieve adequate power if unverified ICD-9-CM codes are used, especially when vaccine associations are weak.

CONCLUSIONS

ICD-9-CM codes for type 1 diabetes in children, intussusception in young children, childhood seizures in inpatient and emergency care settings, and inpatient demyelinating disease in adults were sufficiently predictive for vaccine safety analyses to rely on unverified diagnosis codes. Adverse event misclassification should be accounted for in statistical power calculations.

Simulation of a birdcage and a ceramic cavity HF-resonator for high magnetic fields in magnetic resonance imaging

The aim of this work was the 3D-simulation of a dielectric resonator for high-field-MRI. A 12-rod-bird-cage-resonator was simulated in a first step, in order to verify the capability of the commercial simulation software MAFIA to simulate homogeneous, transversal B-fields in resonators. The second step was the simulation of frequency-independent dielectric ceramic resonators for static magnetic field strengths of 7 T and 12 T (294 MHz and 504 MHz respectively). The results were compared to the measured results of a manufactured TiO2- and a Al2O3-resonator. Only minor deviations showed up. These results led to the conclusion that dielectric resonators for high field MRI can be optimised using numerical field calculation software.

Measles-mumps-rubella and other measles-containing vaccines do not increase the risk for inflammatory bowel disease: a case-control study from the Vaccine Safety Datalink project

CONTEXT

A link between measles virus-containing vaccines and inflammatory bowel disease (IBD) has been suggested by recent studies.

OBJECTIVE

To address whether receipt or timing of measles-containing vaccine (MCV) increases risk for IBD.

DESIGN

A case-control study.

SETTING

Four large health maintenance organizations (HMOs) that are part of the Centers for Disease Control and Prevention's Vaccine Safety Datalink project.

PATIENTS OR OTHER PARTICIPANTS

A total of 155 persons with codes from International Classification of Diseases, Ninth Revision specific for IBD, born between 1958 and 1989 and enrolled from birth to the onset of disease, were identified. Up to 5 controls were matched by sex, HMO, and birth year.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Risk for IBD, Crohn's disease, and ulcerative colitis.

RESULTS

Past vaccination was not associated with an increased risk for Crohn's disease (odds ratio [OR] for measles-mumps-rubella vaccine [MMR], 0.4; 95% confidence interval [CI], 0.08-2.0), ulcerative colitis (OR, 0.8; 95% CI, 0.18-3.56), or IBD (OR, 0.59; 95% CI, 0.21-1.68). Risk for IBD was not increased among children vaccinated who were younger than 12 months (OR for MMR, 0.61; 95% CI, 0.15-2.45) or aged 12 to 18 months (OR, 0.86; 95% CI, 0.28-2.59) relative to unvaccinated children. Children vaccinated with MMR who were older than 18 months were at significantly decreased risk for IBD (OR, 0.16; 95% CI, 0.04-0.68). Neither past vaccination nor age at vaccination with other MCV was associated with increased risk for Crohn's disease, ulcerative colitis, or IBD. Risk for Crohn's disease, ulcerative colitis, or IBD was not elevated in the time immediately following vaccination with either vaccine.

CONCLUSIONS

Vaccination with MMR or other MCV, or the timing of vaccination early in life, did not increase the risk for IBD.

Typing of Pasteurella multocida from haemorrhagic septicaemia in Danish fallow deer (Dama dama)

Isolates of Pasteurella multocida ssp. multocida (n = 31) from a Danish population of fallow deer which succumbed to haemorrhagic septicaemia during 1992 1993 and isolates from the palatine tonsils of apparently healthy fallow deer from the same area (n=6) were typed and compared with P. multocida from other sources. Plasmids were net observed in the fallow deer strains and one unique pattern was observed by ribotyping using HindIII and by pulsed-field gel electrophoresis using SanlI as restriction endonuclease. All Danish fallow deer isolates belonged to serotype B:3,4. On restriction endonuclease analysis using HhaI as restriction endonuclease, all had a profile identical to that of a fallow deer isolate from the United Kingdom: profile 0033 of Wilson et al. On restriction endonuclease analysis using HpaII as restriction endonuclease, the Danish fallow deer isolates had a unique profile, designated 0062, which differed slightly from that of a fallow deer isolate from the United Kingdom. P. multocida from other animal species were genotypically different from the fallow deer isolates. It is concluded that a specific clone of P. multocida was responsible for the outbreak of haemorrhagic septicaemia among Danish fallow deer. A carrier rate of 27% was demonstrated among apparently normal animals from the same population.

Hemorrhagic septicemia in fallow deer (Dama dama) caused by Pasteurella multocida multocida

Four outbreaks of hemorrhagic septicemia caused by Pasteurella multocida multocida occurred in a population of 1,800 fallow deer (Dama dama) during 1992-1996. A total of 340 fallow deer were submitted for postmortem examination. Pasteurellosis was diagnosed in 273 of 312 deer suspected of having septicemia. Pasteurella multocida was isolated from 257 animals, and the diagnosis was based on typical pathologic changes alone in the other 16 animals. Pasteurella multocida was isolated in pure culture from 219 of 248 samples of cerebrospinal fluid. Eighteen animals were observed moribund with severe depression, foamy nasal discharge, and respiratory distress, and 257 were found dead. Major clinical signs and pathologic changes included extensive swelling of the head and the neck and peracute or acute septic pneumonia, petechial and ecchymotic hemorrhages on serous membranes, and severely hemorrhagic adrenal glands and abomasum. Rhinitis and necrotic pharyngeal mucosae were common. Histologically, the most advanced lesions were in the nasal mucosa and pharynx. The swelling of the head and the neck arose from a diffuse cellulitis in the subcutaneous and intermuscular tissues. The earliest lesions in the lungs included large numbers of bacteria in the pulmonary capillaries, but various degrees of fibrinous exudation to the alveoli and infiltration with heterophils usually were observed.

Validation of wall thickness estimates obtained with polarized light microscopy using multiple fluorochrome labels: correlation with erosion depth estimates obtained by lamellar counting

Numerous methods are currently being employed to estimate completed wall thickness and final erosion depth. Conflicting estimates of calculated bone balance have been obtained from the estimates of wall thickness and erosion depth using these various methods. To assess the utility of two specific methods to estimate wall thickness (polarized microscopy) and erosion depth (lamellar counts), we conducted a study in normal young adult beagle dogs, a model where bone balance should approximate 0. Dogs were administered multiple fluorochrome labels in vivo to label activity forming bone pockets. These labels were used to confirm the position of the cement line of the bone structural unit (BSU) in fluorescent light. Parallel measurements of wall thickness were then collected in polarized light. These estimates were compared to estimates of erosion depth obtained by lamellar counting and bone balance was calculated. Estimates of wall thickness correlated well with estimates of erosion depth with bone balance not differing significantly from 0. These data suggest that the combination of these two methods is a reasonable approach to obtaining estimates of bone balance at the level of the remodeling unit.

Midsagittal dimensions of the prenatal human cranium

The purpose of the present study was to analyze the linear dimensions of the cranial base and the anterior facial heights in the median plane of human fetal crania during the second trimester. The distances measured were related to gestational age (GA), crown-rump length (CRL) and maturation stages of the cranial base (MSS). The material comprised midsagittal tissue blocks of the crania from 52 normal human fetuses aged 13 to 22 weeks GA with CRL from 78 to 230 mm and cranial base maturation from MSS 3 to MSS 7. The measurements of the cranial and facial dimensions were performed on radiographs of these tissue blocks. The study confirmed previous observations regarding the dimensional increase in the linear dimensions of the cranial base and the upper facial height in the second trimester. The assessment of absolute changes was further supplemented by an analysis of the percentage changes. This analysis showed that the percentage changes from MSS 3 to MSS 7 of the linear dimensions of the cranial base and the upper facial heights were similar. On the other hand, the percentage increase in the lower anterior facial height during the second trimester was found to be much larger than that of the cranial base and the upper anterior facial height. It is suggested that this is related to the marked increase of the tooth germs during the period and the concurrent growth of the alveolar processes. Standards for normal prenatal cranial dimensions in relation to stages of maturation in the midsagittal cranial base were provided. These data may be of value for use in prenatal diagnostics.

Protection provided by Haemophilus influenzae type b conjugate vaccines in Los Angeles County: a case-control study

The objective was to assess the degree of disease control and to evaluate the protective efficacy of licensed Haemophilus influenzae type b (Hib) conjugate vaccines (HbOC, PRP-OMP, PRP-D) used routinely in children 2 to 35 months of age. We conducted a case-control study in Los Angeles County between January 1, 1991, and December 31, 1992, and a cohort analysis of Hib cases between 1983 and 1992. For the case-control study 105 cases of invasive Hib disease were identified and 767 geographically and age-matched controls were selected by random digit telephone dialing. Sixteen HbOC vaccine failures occurred > 14 days after a single dose of vaccine, 6 vaccine failures after 2 doses and 3 failures after 3 doses; 2 cases occurred 6 and 12 days, respectively, after an initial dose of HbOC. The protective efficacy of a single HbOC vaccine dose was 71.1% (95% confidence interval (CI), 37.5 to 87.2%). After 2 doses the efficacy was 88.8% (95% CI, 59.5 to 96.9%) and after 3 doses it was 94.4% (95% CI, 68.0% to 99.0%). Similar 95% CIs were seen for 1 and 2 doses of PRP-OMP vaccine. Adjustment of efficacy estimates for potential confounding variables did not significantly alter the results. Despite relatively low rates of immunization (20 to 60%) the rates of Hib disease decreased strikingly between 1990 and 1992 (from 24.2 to 4.4/100,000 children < 5 years of age). The HbOC conjugate vaccine, used predominantly but incompletely during this period, provided substantial protection against invasive Hib disease in children immunized between 2 and 35 months of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Eradication of Haemophilus influenzae type b disease in southern California. Kaiser-UCLA Vaccine Study Group

OBJECTIVE

To assess the effects of Haemophilus influenzae vaccination of infants.

RESEARCH DESIGN

We evaluated H influenzae type b (Hib) disease rates in Los Angeles County, California (population, 9 million; 1983 through 1992), and in the Southern California Kaiser Health Plan (2.5 million enrollees; 1988 through 1992) during the past decade. Cases were obtained through active and passive disease surveillance in the two populations. The following vaccines were used during the study period (1983 through 1992): (1) Hib polysaccharide vaccine (polyribosyl ribitol phosphate) (used from 1985 through 1987 for children 24 through 60 months of age); (2) Hib polysaccharide-diphtheria toxoid conjugate, Hib polysaccharide CRM197 mutant diphtheria toxoid conjugate vaccine, and Hib polysaccharide outer-membrane protein of group B meningococcus conjugate vaccine in older children (1988 through 1990; ages 15 through 60 months); and (3) Hib polysaccharide CRM197 mutant diphtheria toxoid conjugate vaccine and Hib polysaccharide outer-membrane protein of group B meningococcus conjugate vaccine used in infants (1991 through 1992).

MEASUREMENTS AND RESULTS

Between 1983 and 1988, the Hib disease incidence in Los Angeles County was unchanged (32.7 to 42.5/100,000 person-years in children younger than 5 years). In 1989 through 1990, before Hib conjugate licensure for infant use, Hib disease rates in all age groups declined. After licensure of Hib vaccines for infants in 1990, there was a further fivefold decrease in infants. More dramatic decreases occurred in the better-immunized Kaiser Health Plan children aged 0 through 60 months (53 cases in 1989, only two cases in 1992).

CONCLUSIONS

The Hib disease has been nearly eradicated in a fully immunized population (Kaiser Health Plan), and significant reductions have also occurred in Los Angeles County.

Linearity of cephalometric digitizers

The present study aimed to develop a test procedure to diagnose and visualize errors in linearity of digitizing tablets. Errors of linearity are caused by the distortion of the x- and y-co-ordinates of the digitizing tablet. This results in a given object apparently having different dimensions when recorded on different locations of the digitizing surface. The test is performed by systematic recording of n equally spaced points from a calibrated test foil. Algorithms were developed to calculate the difference matrices DXji and DYji between expected and observed values of the co-ordinates. Three-dimensional mapping of the non-linearity of the x- and y-co-ordinates was performed by the UNIRAS-geopak, a 3-D surface representative system. The tested digitizers showed varying degrees of scaling errors, fields of non-linearity, and random noise. Most digitizers allow for correction of scaling by setting of switches in the control unit. A method is suggested for correction of non-linearities by use of the DXji and DYji matrices in the digitizing programme.

Influence of skin graft pathology on residual ridge reduction after mandibular vestibuloplasty. A 5-year clinical and radiological follow-up study

The present study is a 5-year clinical and radiographic follow-up of 51 patients who had undergone a combined vestibuloplasty with a split skin graft and lowering of the floor of the mouth. Our purpose was to examine the effect of clinically evident graft pathology on the residual ridge reduction. The clinical records of the graft condition were classified into: healthy graft, partial loss of keratinization, and total loss of keratinization. The residual ridge reduction was monitored by ridge height measurements at different locations, and by the symphyseal and mandibular body areas. Patients with clinical signs of graft pathology (reddening, loss of keratinization) suffered a significantly more severe residual ridge reduction than those with a healthy skin graft (p less than 0.01). Subsequent findings including smear tests showing Candida albicans hyphae, and improvement of graft condition after antimycotic therapy, indicated that the graft pathology observed is a candidiasis.

Thyroid function tests in patients undergoing bone marrow transplantation

Thyroid function was studied prospectively in 27 patients receiving bone marrow transplants to determine the effect of this procedure and its sequelae on serum thyroid hormone levels and thyrotropin secretion. Serum triiodothyronine and free triiodothyronine concentrations declined to subnormal levels in nearly all of the patients; free thyroxine concentration became subnormal in 15 patients. At the time of the nadir of the serum T3 concentration, serum thyrotropin concentration, measured by a sensitive immunoradiometric assay, declined significantly and became subnormal in nine patients. The data suggest that the reduction of serum thyroxine levels after transplantation is attributable, at least in part, to inhibition of thyrotropin secretion.

Reduction of mandibular residual ridge after vestibuloplasty. A two-year follow-up study comparing the Edlan flap, mucosal and skin graft operations

Mandibular residual ridge reduction (RRR) after Edlan flap vestibuloplasty, buccal mucosal graft, and split skin graft vestibuloplasty was measured on lateral cephalometric radiographs obtained 1, 3, 6, 12 and 24 months postsurgery in 50 patients. The ridge reduction was most severe during the immediate postoperative period. The different operation methods did not give rise to significant variations in the reduction pattern, neither did the sex of the patient appear to be an important factor. The temporary increase of mandibular resorption after vestibuloplasty surgery is of a magnitude comparable to the average RRR during 1 year in full denture wearers with a long denture experience.

Evidence of steroid receptors in human osteoblast-like cells

A nuclear binding assay was used to demonstrate steroid receptors in normal human osteoblast-like cells. Nuclear binding of [3H]estradiol was found in 27 of 30 (90%) cell strains and nuclear binding of [3H]androgen was identified in 21 of 25 (84%) separate osteoblast cell strains. The nuclear binding was saturable and steroid-specific. Estrogen and androgen receptor gene expression was confirmed by RNA blot analysis. These data suggest that circulating sex steroids may act directly on normal human osteoblasts through receptor-mediated mechanisms.

An outbreak of meningo-encephalitis in fallow deer caused by Listeria monocytogenes

An outbreak of listeric meningo-encephalitis occurred in a population of 1800 fallow deer (Dama dama) in a park during the winter and early spring of 1985 to 1986. Listeriosis was diagnosed in 41 of 42 fallow deer that showed the typical central nervous system signs of circling disease or were found dead. The diagnosis was verified by bacteriological examination of the brains of 35 animals. In five of the seven remaining cases listeriosis was diagnosed by histological examination, and in one animal by clinical signs alone. Listeria monocytogenes was isolated in three of 23 soil samples taken from the park. In addition, L monocytogenes was isolated from the intestinal contents of apparently normal fallow deer. Fifty isolates from animals and soil were serotyped and all of them belonged to serovar 4b except one from brain (serovar 1/2b) and three from intestinal contents (serovar 1/2a). In phage typing of 54 isolates, the 35 isolates from the brain and spleen of diseased animals belonged to the same lysovar, as did most isolates from other sources, but strains from intestinal contents belonged to three other phage types. No external source of L monocytogenes was demonstrated in the outbreak and stress due to the poor beech-mast crop, an increased stocking rate and a sudden change in the weather are suspected as predisposing factors.

Nonenzymatic glucosylation of lysyl and hydroxylysyl residues in type I and type II collagens

Nonenzymatic glucosylation of type I and type II collagens was examined by incubating collagen substrates with D-glucose in vitro. In one set of experiments, unlabeled collagen was incubated with [14C]-glucose and the incorporation of [14C]-radioactivity into protein was determined by TCA precipitation. The incorporation was dependent on the concentration of glucose and the time of incubation. The glucosylated product was also examined by SDS-polyacrylamide slab gel electrophoresis. The results indicated that both alpha 1(I)- and alpha 2(I)-chains of type I collagen were glucosylated and the glucosylation occurred both with native and denatured collagen as substrate. In further studies [3H]-lysine-labeled collagens were glucosylated, the products reduced by NaBH4, and the [3H]-lysine-derived residues were separated by amino acid analyzer. After a 144 h incubation in vitro, 18.9% of [3H]-lysyl residues and 36.5% of [3H]-hydroxylysyl residues in type I collagen were substituted with glucose. In contrast, 47.9% of [3H]-lysyl residues and 68.1% of [3H]-hydroxylysyl residues in type II collagen were glucosylated after 144 h incubation. Based on quantitative amino acid analyses of the substrates, these values represent 27.6 lysine plus hydroxylysine residues substituted per triple-helical type I collagen molecule and 65.3 residues per triple-helical type II collagen molecule. Thus, type I and type II collagens display differential susceptibilities to nonenzymatic glucosylation. Finally, [3H]-proline-labeled type I collagen was glucosylated to varying extents, and the glucosylated products were used as substrates for human polymorphonuclear leukocyte collagenase. No difference in susceptibility to this collagenase was noted, irrespective of the extent of glucosylation.