Target setting in intensive insulin management is associated with metabolic control: the Hvidoere childhood diabetes study group centre differences study 2005

OBJECTIVE

To evaluate glycaemic targets set by diabetes teams, their perception by adolescents and parents, and their influence on metabolic control.

METHODS

Clinical data and questionnaires were completed by adolescents, parents/carers and diabetes teams in 21 international centres. HbA1c was measured centrally.

RESULTS

A total of 2062 adolescents completed questionnaires (age 14.4 +/- 2.3 yr; diabetes duration 6.1 +/- 3.5 yr). Mean HbA 1c = 8.2 +/- 1.4% with significant differences between centres (F = 12.3; p < 0.001) range from 7.4 to 9.1%. There was a significant correlation between parent (r = 0.20) and adolescent (r = 0.21) reports of their perceived ideal HbA1c and their actual HbA1c result (p < 0.001), and a stronger association between parents' (r = 0.39) and adolescents' (r = 0.4) reports of the HbA1c they would be happy with and their actual HbA1c result. There were significant differences between centres on parent and adolescent reports of ideal and happy with HbA1c (8.1 < F > 17.4;p < 0.001). A lower target HbA1c and greater consistency between members of teams within centres were associated with lower centre HbA1c (F = 16.0; df = 15; p < 0.001).

CONCLUSIONS

Clear and consistent setting of glycaemic targets by diabetes teams is strongly associated with HbA1c outcome in adolescents. Target setting appears to play a significant role in explaining the differences in metabolic outcomes between centres.

Are family factors universally related to metabolic outcomes in adolescents with Type 1 diabetes?

AIMS

To assess the importance of family factors in determining metabolic outcomes in adolescents with Type 1 diabetes in 19 countries.

METHODS

Adolescents with Type 1 diabetes aged 11-18 years, from 21 paediatric diabetes care centres, in 19 countries, and their parents were invited to participate. Questionnaires were administered recording demographic data, details of insulin regimens, severe hypoglycaemic events and number of episodes of diabetic ketoacidosis. Adolescents completed the parental involvement scale from the Diabetes Quality of Life for Youth--Short Form (DQOLY-SF) and the Diabetes Family Responsibility Questionnaire (DFRQ). Parents completed the DFRQ and a Parental Burden of Diabetes score. Glycated haemoglobin (HbA(1c)) was analysed centrally on capillary blood.

RESULTS

A total of 2062 adolescents completed a questionnaire, with 2036 providing a blood sample; 1994 parents also completed a questionnaire. Family demographic factors that were associated with metabolic outcomes included: parents living together (t = 4.1; P < 0.001), paternal employment status (F = 7.2; d.f. = 3; P < 0.001), parents perceived to be over-involved in diabetes care (r = 0.11; P < 0.001) and adolescent-parent disagreement on responsibility for diabetes care practices (F = 8.46; d.f. = 2; P < 0.001). Although these factors differed between centres, they did not account for centre differences in metabolic outcomes, but were stronger predictors of metabolic control than age, gender or insulin treatment regimen.

CONCLUSIONS

Family factors, particularly dynamic and communication factors such as parental over-involvement and adolescent-parent concordance on responsibility for diabetes care appear be important determinants of metabolic outcomes in adolescents with diabetes. However, family dynamic factors do not account for the substantial differences in metabolic outcomes between centres.

Persistent differences among centers over 3 years in glycemic control and hypoglycemia in a study of 3,805 children and adolescents with type 1 diabetes from the Hvidøre Study Group

OBJECTIVE

Twenty-one international pediatric diabetes centers from 17 countries investigated the effect of simple feedback about the grand mean HbA(1c) level of all centers and the average value of each center on changes in metabolic control, rate of severe hypoglycemia, and insulin therapy over a 3-year period.

RESEARCH DESIGN AND METHODS

Clinical data collection and determination of HbA(1c) levels were conducted at a central location in 1995 (n = 2,780, age 0-18 years) and 1998 (n = 2,101, age 11-18 years).

RESULTS

Striking differences in average HbA(1c) concentrations were found among centers; these differences remained after adjustment for the significant confounders of sex, age, and diabetes duration. They were apparent even in patients with short diabetes duration and remained stable 3 years later (mean adjusted HbA(1c) level: 8.62 +/- 0.03 vs. 8.67 +/- 0.04 [1995 vs. 1998, respectively]). Three centers had improved significantly, four centers had deteriorated significantly in their overall adjusted HbA(1c) levels, and 14 centers had not changed in glycemic control. During the observation period, there were increases in the adjusted insulin dose by 0.076 U/kg, the adjusted number of injections by 0.23 injections per day, and the adjusted BMI by 0.95 kg/m(2). The 1995 versus 1998 difference in glycemic control for the seven centers could not be explained by prevailing insulin regimens or rates of hypoglycemia.

CONCLUSIONS

This study reveals significant outcome differences among large international pediatric diabetes centers. Feedback and comparison of HbA(1c) levels led to an intensification of insulin therapy in most centers, but improved glycemic control in only a few.

Insulin management and metabolic control of type 1 diabetes mellitus in childhood and adolescence in 18 countries. Hvidøre Study Group on Childhood Diabetes

Insulin regimens and metabolic control in children and adolescents with Type 1 diabetes mellitus were evaluated in a cross-sectional, non-population-based investigation, involving 22 paediatric departments, from 18 countries in Europe, Japan, and North America. Blood samples and information were collected from 2873 children from March to August 1995. HbA1c was determined once and analysed centrally (normal range 4.4-6.3%, mean 5.4%). Year of birth, sex, duration of diabetes, height, body weight, number of daily insulin injections, types and doses of insulin were recorded. Average HbA1c in children under 11 years was 8.3 +/- 1.3% (mean +/- SD) compared with 8.9 +/- 1.8% in those aged 12-18 years. The average insulin dose per kg body weight was almost constant (0.65 U kg(-1) 24 h(-1)) in children aged 2-9 years for both sexes, but there was a sharp increase during the pubertal years, particularly in girls. The increase in BMI of children with diabetes was much faster during adolescence compared to healthy children, especially in females. Sixty per cent of the children (n = 1707) used two daily insulin injections while 37% (n = 1071) used three or more. Of those on two or three injections daily, 37% used pre-mixed insulins, either alone or in combination with short- and intermediate-acting insulin. Pre-adolescent children on pre-mixed insulin showed similar HbA1c levels to those on a combination of short- and long-acting insulins, whereas in adolescents significantly better HbA1c values were achieved with individual combinations. Very young children were treated with a higher proportion of long-acting insulin. Among adolescent boys, lower HbA1c was related to use of more short-acting insulin. This association was not found in girls. We conclude that numerous insulin injection regimens are currently used in paediatric diabetes centres around the world, with an increasing tendency towards intensive diabetes management, particularly in older adolescents. Nevertheless, the goal of near normoglycaemia is achieved in only a few.

Ketoacidosis at the diagnosis of type 1 (insulin dependent) diabetes mellitus is related to poor residual beta cell function. Childhood Diabetes in Finland Study Group

The determinants of the degree of metabolic decompensation at the diagnosis of type 1 (insulin dependent) diabetes mellitus (IDDM) and the possible role of diabetic ketoacidosis in the preservation and recovery of residual beta cell function were examined in 745 Finnish children and adolescents. Children younger than 2 years or older than 10 years of age were found to be more susceptible to diabetic ketoacidosis than children between 2 and 10 years of age (< 2 years: 53.3%; 2-10 years: 16.9%; > 10 years: 33.3%). Children from families with poor parental educational level had ketoacidosis more often than those from families with high parental educational level (24.4% v 16.9%). A serum C peptide concentration of 0.10 nmol/l or more was associated with a favourable metabolic situation. Low serum C peptide concentrations, high requirement of exogenous insulin, low prevalence of remission, and high glycated haemoglobin concentrations were observed during the follow up in the group of probands having diabetic ketoacidosis at the diagnosis of IDDM. Thus diabetic ketoacidosis at diagnosis is related to a decreased capacity for beta cell recovery after the clinical manifestation of IDDM in children.

Serum insulin profiles in consecutive children 2 years after the diagnosis of IDDM

We studied associations of 24-h serum insulin profiles with insulin dose, age, gender, haemoglobin A1c (HbA1c) and C-peptide values, as well as blood glucose profiles in 77 consecutive children-nine aged 2-4, 14 aged 5-8, 26 aged 9-12, and 28 aged 13-17 years--2 years after the onset of insulin-dependent diabetes mellitus (IDDM). Mean weight-based insulin doses in the four age groups were similar (0.7 +/- 0.2 U.kg-1.day-1 in all); body surface-area-based doses differed. Insulin doses correlated significantly with the 24-h mean and area-under-the-curve (AUC) values, and with mean values at 03.00 hours of serum insulin in the children aged 5-8 and 13-17 years. The mean insulin concentrations of the age groups (95% confidence intervals) increased with age [6.1 (3.8, 9.7), 7.6 (5.9, 9.8), 10.4 (8.6, 12.4), and 14.0 (11.6, 16.8) mU/l; p < 0.0002]. The 24-h mean of serum insulin together with HbA1c concentration predicted 32% of the variation of mean blood glucose concentrations. Of children aged less than 9 years, 50% had insulin values less than 5 mU/l (healthy subjects' lower reference limit), and 14% were of less than 2 mU/l (detection limit of the assay) at 03.00 hours. At 07.00 hours, 82% had insulin values of less than 5 mU/l, and 36% were of less than 2 mU/l, respectively. Some young children had night-time hypoglycaemia with simultaneous hypoinsulinaemia. Insulin profiles correlated poorly with the HbA1c and peak C-peptide values.(ABSTRACT TRUNCATED AT 250 WORDS)

Clarithromycin vs. amoxicillin suspensions in the treatment of pediatric patients with acute otitis media

Clarithromycin is a new macrolide antibiotic that is active in vitro against a variety of organisms that are responsible for acute otitis media in children. The parent compound is metabolized to microbiologically active 14-hydroxy clarithromycin, which is especially active against Haemophilus influenzae. The safety and efficacy of clarithromycin and amoxicillin suspensions were compared in the treatment of acute otitis media in children 1 to 12 years of age inclusive. This was a Phase III, single blind (investigator-blind), randomized, multicenter clinical trial. Clarithromycin oral suspension was given in a dose of 7.5 mg/kg (maximum, 500 mg) twice daily, and amoxicillin suspension in a dose of 20 mg/kg (maximum, 750 mg) was given twice daily for 7 to 10 days in a 1:1 ratio. Clinical evaluations were performed pretreatment, within 48 hours posttreatment and 10 to 14 days posttreatment. Myringotomy was performed in every child to obtain a microbiologic sample pretreatment and at subsequent visits as clinically indicated. A total of 79 children were enrolled, 39 in the clarithromycin and 40 in the amoxicillin treatment group. Thirty-two children were excluded from the efficacy analysis for various reasons. Clinical success (cure and improvement) rates at 0 to 4 days posttreatment were 93% for clarithromycin and 90% for amoxicillin (P > 0.999). Altogether 17 children (10 receiving clarithromycin, 7 receiving amoxicillin) experienced some adverse event, with gastrointestinal disorders being the most common complaint. No clinically significant differences in laboratory tests were found between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Glucose profiles in children two years after the onset of type 1 diabetes

The relationship of 24-h glucose profiles to age, haemoglobin A1c (HbA1c), and C-peptide concentration was analysed in consecutive, unselected children who had developed Type 1 diabetes 2 years earlier. Seventy-seven children in four age groups (age 2-4 years, n = 9; 5-8 years, n = 14; 9-12 years, n = 26; and 13-17 years, n = 28) were studied. Each child was hospitalized for 2 days for the investigations. Mean blood glucose concentration was 9.7 +/- 4.1 (SD) mmol l-1 in children aged 2-4 years; 10.7 +/- 4.0 mmol l-1 in those aged 5-8 years; 11.3 +/- 3.4 mmol l-1 in those aged 9-12 years; and 9.8 +/- 3.3 mmol l-1 in those aged 13-17 years. Results were > 7.0 mmol l-1 in 69% (range 56-76%) and > 10 mmol l-1 in 49% (39-57%) of the measurements. Values decreased by 30% (21-43%) between 10 pm and 3 am. The nadir of the mean profiles of the groups was always at 3 am. Glucose concentration was mmol l-1 in 25% (14-50%), < 2.5 mmol l-1 in 9.6% (0-21%), and < 2.0 mmol l-1 in 2.7% (0-4.2%) of the children at 3 am; hypoglycaemia was most common in those aged 5-8 years. Of the four profile characteristics used, mean blood glucose predicted HbA1c (R2 = 24.7%, p < 0.00005, multiple linear regression analysis), and slightly more in combination with age (R2 = 32.0%, p < 0.00005).(ABSTRACT TRUNCATED AT 250 WORDS)

Associations of serum lipids with metabolic control and diet in young subjects with insulin-dependent diabetes mellitus in Finland

Association of serum lipids with metabolic control and diet were studied in 72 young subjects with insulin-dependent diabetes mellitus (IDDM). Data on food consumption were collected by the 48-h recall method. Glycosylated haemoglobin (Hb) A1 was used as a measure of metabolic control. There were no differences between males and females in the mean values for serum total cholesterol (TC, 4.5 and 4.9 mmol/l, respectively), low density lipoprotein cholesterol (LDL-C, 2.7 and 3.0 mmol/l), high density lipoprotein cholesterol (HDL-C, 1.3 and 1.4 mmol/l), or serum triglycerides (TG, 1.1 and 1.0 mmol/l). Diabetic subjects who were in better metabolic control (HbA1 < 10.5%), when compared with those in poorer control (HbA1 > or = 10.5%) had lower TC and TG values and a higher HDL-C/TC ratio. HbA1 level and intake of saturated fatty acids were positively associated with serum TC and LDL-C values and explained 14% and 15% of the variation in TC and LDL-C, respectively. HbA1 level and insulin dose per kg of body weight were positively associated with serum TG values and explained 30% of the variation in TG. Serum TC and LDL-C levels of young subjects with IDDM could be lowered by improving their metabolic control and decreasing their saturated fatty acid intake.

Epidemiology of childhood diabetes mellitus in Finland--background of a nationwide study of type 1 (insulin-dependent) diabetes mellitus. The Childhood Diabetes in Finland (DiMe) Study Group

A nationwide study of childhood Type 1 (insulin-dependent) diabetes mellitus was established in 1986 in Finland, the country with the highest incidence of this disease worldwide. The aim of the project called "Childhood Diabetes in Finland" is to evaluate the role of genetic, environmental and immunological factors and particularly the interaction between genetic and environmental factors in the development of Type 1 diabetes. From September 1986 to April 1989, 801 families with a newly-diagnosed child aged 14 years or younger at the time of diagnosis were invited to participate in this study. The vast majority of the families agreed to participate in the comprehensive investigations of the study. HLA genotypes and haplotypes were determined in 757 families (95%). Our study also incorporates a prospective family study among non-diabetic siblings aged 3-19 years, and two case-control studies among the young-onset cases of Type 1 diabetes. During 1987-1989, the overall incidence of Type 1 diabetes was about 35.2 per 100,000 per year. It was higher in boys (38.4) than in girls (32.2). There was no clear geographic variation in incidence among the 12 provinces of Finland. Of the 1,014 cases during these 3 years only six cases were diagnosed before their first birthday. The incidence was high already in the age group 1-4-years old: 33.2 in boys and 29.5 in girls. Of the 801 families 90 (11.2%) were multiple case families, of which 66 had a parent with Type 1 diabetes at the time of diagnosis of the proband.(ABSTRACT TRUNCATED AT 250 WORDS)

Randomised prospective study of short-term and long-term initial stay in hospital by children with diabetes mellitus

To assess how an isolated change in the pattern of care influences outcome of care and hospital use, a randomised prospective 2-year study was done in which 31 of 61 consecutive children with newly diagnosed insulin-dependent diabetes mellitus (IDDM) were admitted to hospital at disease onset for about a week and compared with the other 30 children who were admitted for about 4 weeks. Insulin treatment and education about diabetes were similar in the two groups. Duration of initial stay in hospital had no effect on metabolic control during the 2 years but time since diagnosis was significant with respect to effect on haemoglobin A1 (p = 0.001), haemoglobin A1c (p = 0.004), and insulin dose (p less than 0.001). At 2 years, 45% of the children in the short-term group and 29% in the long-term group were C-peptide positive (p = NS); C-peptide positivity correlated with age. A change in the pattern of care of children with IDDM, led to a pronounced decrease in hospital use by this patient group. Irrespective of the length of initial stay in hospital, equally good metabolic control was obtained in both groups for 2 years.

Serum insulin and other cardiovascular risk indicators in children, adolescents and young adults

We wanted to determine the levels of fasting serum insulin during growth, the tracking of serum insulin, and the correlation of serum insulin with other coronary heart disease risk indicators in children and young adults. In 1986 2433 subjects, aged nine to 24 were studied, and insulin data were available from the same population in 1980 and 1983. Serum insulin levels showed a peak during puberty in both sexes and the decline in insulin continued after the age of 21. Tracking of serum insulin was only moderate, especially in females and young boys. Serum insulin correlated positively with body mass index, concentrations of serum triglycerides, and blood pressure, and inversely with the concentration of high density lipoprotein cholesterol. High triglycerides, high systolic blood pressure, and low level of high density lipoprotein cholesterol clustered among subjects within the highest insulin quartile. Our results suggest that the insulin resistance phenomenon, caused mainly by obesity and leading to unfavourable levels of other coronary heart disease risk indicators, is already developing in children and young adults. This suggests that preventing obesity in early life is important.

Serum lipids and lipoproteins in children, adolescents and young adults in 1980-1986

A multicentre study on atherosclerosis precursors in young Finns aged three to 18 years was started in 1980 (3596 subjects) serum lipid concentrations (cholesterol, HDL (high density lipoprotein) cholesterol and triglycerides) were determined (n = 3554) and the apolipoproteins A-I and B measured (n = 1355). Two follow-up studies were carried out in 1983 (n = 2851) and 1986 (n = 2489), when HDL-subfractions (HDL-2-cholesterol and HDL-3-cholesterol) were also determined. Apolipoproteins A-I and B were measured again in 1986 (n = 1202). Serum total cholesterol concentration has fallen by about 1% annually during the 1980's from 5.07 mmol/l (1980) to 4.79 mmol/l (1986) in 9- to 18-year old children and adolescents. Mean values of serum triglycerides have slightly increased during the follow-up from 0.79 mmol/l to 0.84 mmol/l, respectively. In children and young adults (3-24 years) the mean cholesterol concentration was highest at the age of six and lowest during puberty. Concentrations of serum cholesterol, LDL (low density lipoprotein) cholesterol apoprotein B and triglycerides were higher in eastern than in western Finland in 1980 and 1983, but these differences were smaller in 1986, with the exception of serum triglycerides. Both in 1983 and in 1986 HDL-2-cholesterol was lower in the west than in the east, whereas HDL-3-cholesterol was higher in the former. The favourable changes in lipid levels should be reflected in future morbidity and mortality rates from coronary heart disease in Finland.

Blood pressure in children, adolescents and young adults

The question of whether blood pressure is one of the main risk factors for cardiovascular diseases in childhood has been evaluated in a Study of Cardiovascular Risk in Young Finns. In the second follow-up study, carried out in 1986, blood pressure was successfully measured in 2500 individuals aged nine to 24 years using a random zero sphygmomanometer. The mean systolic blood pressure in girls rose from 102 mmHg (95th percentile 119 mmHg) at age nine to 116 mmHg (138 mmHg) at age 24 and that in boys from 102 mmHg (95th percentile 121 mmHg) to 128 mmHg (148 mmHg). Diastolic blood pressure was more often measurable using Korotkoff's 5th than the 4th phase. The values observed were similar to those reported by the Second Task Force on Blood Pressure Control in Children, but owing to differences in the methods used to measure blood pressure it cannot be reliably concluded that the blood pressures were similar in the two series. Even in childhood blood pressure measurement is important, and since it changes with the physical size of the child, observations should be compared with normal values such as those reported here. No data are yet available to suggest that children with blood pressure values in the high normal range would benefit from interventions. Thus normal blood pressure value curves should be applied with caution when assessing children.

Predictive validity of preadolescent type A determinants for type A dimensions in young adulthood--a 6-year follow-up

This study examined the predictive validity of preadolescent Type A determinants for Type A dimensions in young adulthood (n = 375). Predictive variables, i.e. hyperactivity, aggression, social maladjustment and self-esteem were measured when the subjects were aged 12. Type A dimensions, i.e. hard-driving, competitiveness plus aggression and impatience were measured in the same subjects when they were aged 18. "Impatience" was predicted by means of preadolescent hyperactivity, and "competitiveness-aggression" by social maladjustment. "Hard-driving", which was most strongly related to CHD risk factor levels in young adulthood, was anteceded by the subject's feeling that he or she could not cope with life. This supports the hypothesis that Type A behaviour is a coping mechanism: a person tries to cope with stress by increasing his or her level of achievement.

Obesity in children, adolescents and young adults

The prevalence of obesity in Finnish children, adolescents and young adults aged three to 24 years was estimated in three surveys performed within the multicentre project, "Cardiovascular Risk in Young Finns" (1980, 1983, 1986). Obesity was defined as either body mass index (weight/height) or skinfold thickness (triceps or subscapular) or both greater than 90th percentiles of age and sex-specific reference data for white children. Its mean prevalences among 9- to 18-year old boys and girls in three surveys (95% confidence limits) were 3.6% (3.1-4.2) and 2.1% (1.7-2.6) as estimated in terms of body mass index and triceps skinfold thickness or 4.3% (3.9-4.9) and 2.6% (2.2-3.1) according to body mass index and subscapular skinfold thickness. Thus the 9- to 18-year old boys were on average more often obese than the girls, but no statistically significant changes in the prevalence of obesity were observed over the period 1980-1986. Body mass index and triceps or subscapular skinfold thicknesses vary in sensitivity as indicators of obesity.

Cardiovascular risk in young Finns

This report describes the general outline and progress of a multicentre study on risk factors of coronary heart disease and their determinants in children and adolescents. "Cardiovascular Risk in Young Finns" comprises a cross-sectional study of 3 to 18-year old subjects in 1980, and follow-up studies in 1983 and 1986 in various parts of Finland, and in 1989 in one of the study areas (Turku). The number of participants in 1980 was 3596 (83.1%) of those invited. In 1983 and 1986 83.2% and 77.8% of them, respectively, participated. The study programme has comprised questionnaire data on, for example, general health and living conditions, physical activity, eating habits, smoking, and psychological variables. The physical examination covered height, weight, skinfold thickness, pubertal stages and blood pressure. Blood specimens were obtained to assess concentrations of serum lipids and insulin, and in 1986 also for possible genetic markers of hypercholesterolemia. A 48 hour recall on nutrient intake was obtained from some of the subjects. The follow-up studies have enabled a study of the tracking phenomenon. Other important questions under study include, for example, the possible clustering of risk factors and their determinants. The cohorts studied provide a valuable research basis for the future, with emphasis on enabling a long-term follow-up of the subjects.

Periodontal status of Finnish adolescents with insulin-dependent diabetes mellitus

The periodontal status of 85 12-18 year-old Finnish adolescents with insulin-dependent diabetes mellitus (IDDM) and their paired, age- and sex-matched healthy controls was assessed clinically and radiographically. The clinical examination consisted of plaque index, gingival index (GI), retentive calculus index, WHO community periodontal index of treatment needs, number of pockets greater than or equal to 4 mm and number of surfaces bleeding after probing. Alveolar bone loss was measured interproximally from the first molars in bite-wing radiographs (all subjects) and from the first incisors in periapical X-rays (patients only). The results show that in spite of similar plaque scores, the patients had higher GI scores and more surfaces bleeding after probing. No differences were found in the number of greater than or equal to 4 mm pockets or radiographical bone loss in the first molars.

Care in diabetic emergencies

A review is presented on the care of three diabetic emergencies: diabetic ketoacidosis (DKA), hypoglycemias and sick days. A treatment scheme, based on low-dose insulin regime and i.v. insulin administration is presented. Plenty of emphasis is laid on fluid and electrolyte therapy. It is stressed that the primary goal in the treatment of DKA is not to reduce blood glucose, but to correct the fluid and electrolyte deficit and by administering insulin to correct the metabolic acidosis and change catabolism into anabolism. The use of bicarbonate in severe DKA is discouraged, and the risk of cerebral edema as a complication of the treatment is stressed. A diabetic child being treated for DKA needs particularly love and care. The three categories of hyperglycemias, mild, moderate, and severe, are briefly reviewed. In severe hypoglycemia (hypoglycemic shock) the treatment is either i.m. glucagon or i.v. glucose. In acute illnesses the use of extra doses of regular insulin is emphasized, in order to prevent DKA.

Morphotypes of the subgingival microflora in diabetic adolescents in Finland

The morphotypes of the subgingival microflora from 85 12 to 18-year-old Finnish adolescents with insulin-dependent diabetes mellitus (IDDM) were studied in Gram- and Rhodes-stained smears. A comparison was made with subgingival plaque samples from paired age- and sex-matched healthy controls. Significant differences were found in the distribution of the morphotypes. The microflora in the IDDM patient group contained significantly lower proportions of Gram-positive and Gram-negative cocci and total Gram-positive bacteria and higher proportions of Gram-negative rods, fusiforms, and total Gram-negative bacteria. In the Rhodes-stained samples, the patients had more straight and curved rods and less fusiforms than the controls. The proportions of spirochetes and flagellated bacteria were almost identical in both groups. The clinical periodontal status of the subjects had been reported in a separate study. In spite of similar Plaque Index scores, the patients had more gingivitis than the controls. This finding may be explained by the distribution of morphotypes: more Gram-negative rods and total Gram-negative bacteria (periodontally more pathogenic forms) in the diabetic patients.

Transfilter evidence for a zone of polarizing activity participating in limb morphogenesis

Barriers were inserted into stage-20 HH chick embryo wing buds to separate the zone of polarizing activity from the anterior two-thirds of the wing bud with its overlying apical ectodermal ridge. Half of the barrier length projected out of the wing bud at insertion. Sham-operated wing buds developed only occasionally into wings with cartilage deletions. After insertion of an impermeable membrane (Cellophane), the typical wing skeleton contained only a humerus and a radius. In order to differentiate between diffusion, cell contact and cell penetration, Nuclepore filters with pore sizes of 0.05 micrometer 1.0 micrometer and 8.0 micrometer, respectively, were inserted. The typical wing skeleton after Nucleopore filter insertion was one with post-axial deletions. None, however, developed with complete distal deletions as after Cellophane. Deletions in the wing skeletons after Nuclepore insertion were the least with 1.0 micrometer filters and the most with 8.0 micrometer filters. Elevation of the apical ectodermal ridge was noted until 18 h after the insertions. In none of the groups did the ridge flatten. The results suggest that the zone of polarizing activity does have a role in normal limb morphogenesis. The mechanism by which its morphogen spreads is diffusion rather than being mediated via cell contacts.

Lack of correlation between mesenchymal cell death and morphogenesis after different extents of apical ectodermal ridge/rim ectoderm removal in the chick embryo wing bud

The removal of the apical ectodermal ridge (A.E.R.) subsequently causes distal deletion defects in the limb. There have been contradictory reports as to the appearance of cell death in the mesenchyme after A.E.R. removal, as well as to its morphogenetic significance. In our study the A.E.R./ rim ectoderm removal was varied to test whether different degrees of cell death would correlate with different degrees of distal deletions. From the right wing bud of stage 19 and 20 (HH) embryos the rim ectoderm was removed in four ways: all of the rim, the anterior third, the middle third (most of the A.E.R.), or its posterior third. The removal of all or of the anterior third caused a definite band of subwound mesenchymal cell death to appear. There was little or no cell death after removal of the middle or posterior thirds. Removal of the anterior third caused no distal deletion defects, and only a few were noted after removal of the posterior third. The proximo-distal level of the distal deletions, however, was the same after removal of all of the rim or only its middle third. As there was no difference in the degree of distal deletions after the removal of all or of the middle third of the rim but a definite difference in the mesenchymal cell death patterns we conclude that cell death is not part of the mechanisms of the distal deletion defect. Our findings also suggest that cell death does not play a role in the A.E.R.-mesenchyme reciprocal interaction that controls limb proximo-distal morphogenesis.