Biocompatibility and osseointegration in osteoporotic bone

We implanted nails made of titanium (Ti6Al4V) and of two types of glass ceramic material (RKKP and AP40) into healthy and osteopenic rats. After two months, a histomorphometric analysis was performed and the affinity index calculated. In addition, osteoblasts from normal and osteopenic bone were cultured and the biomaterials were evaluated in vitro.

In normal bone the rate of osseointegration was similar for all materials tested (p > 0.5) while in osteopenic bone AP40 did not osseointegrate (p > 0.0005).

In vitro, no differences were observed for all biomaterials when cultured in normal bone-derived cells whereas in osteopenic-bone-derived cells there was a significant difference in some of the tested parameters when using AP40.

Our findings suggest that osteopenic models may be used in vivo in the preclinical evaluation of orthopaedic biomaterials. We suggest that primary cell cultures from pathological models could be used as an experimental model in vitro.

Biocompatibility and osseointegration in osteoporotic bone

We implanted nails made of titanium (Ti6Al4V) and of two types of glass ceramic material (RKKP and AP40) into healthy and osteopenic rats. After two months, a histomorphometric analysis was performed and the affinity index calculated. In addition, osteoblasts from normal and osteopenic bone were cultured and the biomaterials were evaluated in vitro. In normal bone the rate of osseointegration was similar for all materials tested (p < 0.5) while in osteopenic bone AP40 did not osseointegrate (p < 0.0005). In vitro, no differences were observed for all biomaterials when cultured in normal bone-derived cells whereas in osteopenic-bone-derived cells there was a significant difference in some of the tested parameters when using AP40. Our findings suggest that osteopenic models may be used in vivo in the preclinical evaluation of orthopaedic biomaterials. We suggest that primary cell cultures from pathological models could be used as an experimental model in vitro.

The effect of osteopenia on the osteointegration of different biomaterials: histomorphometric study in rats

The osteointegration of Hydroxyapatite (HA), Titanium (Ti-6Al-4V: Ti), Zirconia (ZrO2), Alumina (Al2O3) and 2 biological glasses (AP40 and RKKP) was comparatively investigated in normal and osteopenic rats by means of histomorphometry. Thirty-six Sprague Dawley female rats were left intact (Group C) while 36 were ovariectomized (Group OVX). Group C and OVX were further divided into 6 subgroups. After 16 weeks all animals were submitted to the femoral implant of nails made of the above-mentioned materials. Eight weeks after implantation the animals were euthanized, the femurs were harvested for histomorphometric analysis. The data showed that: (1) all the tested materials were biocompatible in vitro; (2) no significant differences existed in Affinity Index (AI) of Group C; and (3) results from paired comparison applied to the AI showed significant differences among the Groups C and OVX. The AI did not significantly change among intact groups, while it significantly decreased when some materials were implanted in OVX subgroups (AP40, ZrO2 and Ti-6Al-4V: p < 0.0005, p < 0.05 and p < 0.01). It is confirmed that bone mineral density is a strong predictor of the osteointegration of an orthopedic implant and that the use of pathological animal models is necessary to completely characterize biomaterials.

Bioactivity modulation of bioactive materials in view of their application in osteoporotic patients

The application of bioactive ceramic coatings to prostheses confers strength to a material (ceramic or biological glass) that exerts beneficial effects on bone-tissue growth but that itself lacks the toughness and stability required of an implant device. The rate of bioactivity is related to the chemical reactivity of the material and causes interface dissolution, precipitation and ion-exchange reactions. Ceramics may differ in sintering temperature and thus exhibit differences in their in vitro dissolution features and in vivo performance. To test these effects, in vitro and in vivo studies were carried out on two biocompatible biological glasses and a ceramic of proven bioactivity in view of their potential utilization as covering materials. In addition, a modified chitosan was adsorbed on the surface of a series of hydroxyapatite (HA) samples. Human fibroblasts and/or osteoblasts were used for the in vitro tests, and normal (INT) and osteoporotic (OVX) rats, normal rabbits and sheep for the in vivo studies. Similar chemical changes were observed in both glasses, suggesting that these materials underwent modifications directly dependent on their biological environment. The in vivo tests point to the possibility of improving the bioactivity of ceramic substrates with chitosan. However, the different behaviour of the materials in vitro and in vivo suggests that these tests should be conducted in parallel.

A biochemical-morphological study on microvillus plasma membrane development

The microvillus plasma membrane of the human placental syncytiotrophoblast at term has been extensively studied, while little is known about the characteristics of its development. The aim of the present work was to compare functional and structural properties of this membrane at early and term gestational age. Ten normal term placentas (40 weeks) and ten placentas at 10 weeks of gestational age were studied. The Na+/K+-ATPase activity is significantly decreased in the syncytiotrophoblast plasma membrane obtained from term placentas as compared to the early ones, with significant variation of maximum velocity (Vmax). The microviscosity, evaluated by the P parameter of DPH and Sn parameters of 5- and 16-NS, is increased in the term placentas compared to the early placentas. This alteration is accompanied by an increased cholesterol to phospholipids ratio in term placentas, while there is a decreased unsaturated to saturated fatty acid ratio. As follows from morphological studies, an increased mean diameter in the E face was observed in the term placenta with respect to the early placenta. The distribution factor DF, which indicates the particle aggregation state, decreased in the E face in the term placenta as compared to the early one. The present biochemical morphological study shows that a deep modification of the membrane is at the basis of the syncytiotrophoblast plasma membrane development.

Antithrombin III infusion suppresses the hypercoagulable state in adult acute lymphoblastic leukaemia patients treated with a low dose of Escherichia coli L-asparaginase. A GIMEMA study

Thrombotic events have been reported in acute lymphoblastic leukaemia patients, especially during or after L-asparaginase administration. A so-called L-asparaginase associated coagulopathy has been well recognized, being characterized by a hypercoagulable state (decrease of antithrombin III, plasminogen, protein C, protein S and increase of prothrombin fragment F1 + 2, thrombin-antithrombin complexes and fibrinopeptide A). The aim of this study was to determine whether the supplementation of antithrombin III (AT-III) concentrates could improve the L-asparaginase associated coagulopathy, thereby blocking the activation of the haemostatic system. In 25 adult patients with acute lymphoblastic leukaemia (M 19, F6, mean age 34 years) antithrombin III (AT-III) concentrates were administered at daily doses of 50 U/kg for 10 consecutive days from the beginning of L-asparaginase therapy (6,000 U/m2/day s.c. for 7 days), given according to the GIMEMA ALL 0288 trial. A marked increase of antithrombin III was recorded on days IV-VIII-XI (P < 0.001). No changes in protein C, protein S, plasminogen, alpha 2-antiplasmin, factor VII and platelet count were observed and there was no increase in markers of hypercoagulability. There was no evidence of disseminated intravascular coagulation. In conclusion, AT-III concentrate supplementation during L-asparaginase therapy, by the achievement of high levels of antithrombin III, is associated with a lack of activation of the haemostatic system and appears to overcome the complex coagulopathy associated with L-asparaginase.

Platelet abnormalities in idiopathic myelofibrosis: functional, biochemical and immunomorphological correlations

BACKGROUND

An extensive study of platelet function was performed on 18 consecutive patients affected by idiopathic myelofibrosis (IM).

MATERIALS AND METHODS

Clinical hematological and morphofunctional parameters were studied in IM patients and control subjects. Platelet tests, ultrastructural data, immunocytochemical von Willebrand factor detection, freeze fracturing results and free cytosolic calcium level were evaluated.

RESULTS

Bleeding time was frequently found to be prolonged, but it never reached levels which could give any cause for concern. Aggregation by ADP, collagen and epinephrine was always altered, sometimes profoundly; on the contrary, agglutination by ristocetin was almost always normal, albeit occasionally increased. Plasma beta-TG and PF4 levels were found to be elevated in 11 and 12 patients, respectively. This indicated an abnormal release from platelet alpha-granules. Depletion of alpha-granules was also confirmed by the intraplatelet von Willebrand factor (vWF) labelling with colloidal gold particles bound to polyclonal antibodies against human vWF. In fact: 1) the number of positive alpha-granules/microm2 and per single platelet was reduced; 2) the intensity of the immunocytochemical reaction for single positive alpha-granules and for each platelet was significantly reduced. Freeze-fracturing studies showed an increase in the number of intra-membrane particles (IMP) on the P face of the platelet membrane with respect to normal platelets preincubated with ADP. However, no differences in their distribution or diameter were observed. High concentrations of free cytosolic calcium were always found and Ca++ ATPase activity was increased. Conversely, Na+/K+ ATPase activity was always reduced.

CONCLUSIONS

We can hypothesize that the platelet membrane is altered in IM, resulting in facilitated activation, even by subliminal stimuli, and that this continuous platelet activation ultimately leads to alpha-granule depletion.

Increased serum levels of transforming growth factor beta-1 in patients affected by thrombotic thrombocytopenic purpura (TTP): its implications on bone marrow haematopoiesis

In this study we evaluated the effect of serum collected from seven thrombotic thrombocytopenic purpura (TTP) patients, either in the acute phase of the disease or in clinical remission, on the in vitro growth of bone marrow haematopoietic progenitor cells, obtained from the same TTP patients in clinical remission and from normal donors. The addition to the cultures of autologous sera collected from TTP patients in acute phase of the disease showed a clear-cut dose-dependent inhibition of immature haematopoietic progenitor cells (BFU-E, CFU-meg and 14th day CFU-GM). On the other hand, no inhibitory effects were observed on more mature 7th day CFU-GM. Interestingly, also sera collected from TTP patients in clinical remission still maintained some inhibitory activity on the growth of immature progenitor cells. A similar inhibitory activity was noticed when TTP sera were tested on normal bone marrow haematopoietic progenitor cells. Such inhibitory activity was significantly reduced in blocking experiments by the addition of a polyclonal neutralizing anti-TGF-beta 1 antibody and the presence of increased levels of both bioactive and latent TGF-beta 1 in TTP sera was confirmed in a bioassay on CCL64 cells. These data contribute to explain the lack of a clear compensatory haematopoiesis observed in some patients with active TTP and add further evidence to the notion of the existence of a state of latent platelet activation in TTP patients in clinical remission.

Recombinant alpha-interferon 2b in the treatment of HIV-related thrombocytopenia

OBJECTIVE

To assess the efficacy and the mechanism of action of alpha-interferon (alpha-IFN) in the treatment of HIV-related thrombocytopenia.

METHODS

Thirteen HIV-positive subjects [nine men and four women with severe thrombocytopenia (platelets, < or = 30 x 10(9)/l)] were treated with alpha-IFN 2b alone at a dose of 3 x 10(6) U three times a week for 5 weeks. Haematological parameters, platelet kinetic and bone-marrow myeloid progenitor cultures [megakaryocyte colony-forming units (CFU-MK); granulocyte macrophage CFU (CFU-GM) and erythroid burst-forming units (BFU-E)] were evaluated before and after treatment in responsive subjects.

RESULTS

Seven out of 13 subjects showed a partial response (platelets, 50-149 x 10(9)/l) after alpha-IFN 2b therapy. Platelet survival as evaluated by 111In-oxine significantly increased, while platelet turnover showed a slight but not statistically significant increase after treatment. The growth of bone-marrow myeloid progenitor cells decreased after alpha-IFN 2b therapy, again without statistical significance.

CONCLUSION

alpha-IFN 2b may increase the platelet count in HIV-positive subjects with severe symptomatic thrombocytopenia by prolonging platelet survival. The immunomodulatory and antiviral action of this drug may be responsible for prolonged platelet survival.

Evidence of a hypercoagulable state in patients with acute lymphoblastic leukemia treated with low dose of E. coli L-asparaginase: a GIMEMA study

Blood coagulation abnormalities induced by administration of E. coli L-asparaginase were investigated in 25 patients with acute lymphoblastic leukemia treated according to the GIMEMA ALL 0288 trial. Dosage of L-asparaginase was relatively low (6,000 U/m2/day for 7 days total dose 42,000 U/m2) as compared to the conventional dosages (120,000-140,000 U/m2 over 10-14 days). A significant decrease in fibronogen, plasminogen, alpha2-antiplasmin and antithrombin III was observed from day IV of L-asparaginase and it was maximum on day VIII, with return to the baseline levels on day XV. Protein C levels had only a borderline reduction, while no modification of protein S or factor VII was observed. Two of the patients investigated developed thrombosis. The presence of a prothrombotic state induced even by this low dosage of E. coli L-asparaginase was suggested by a significant increase of sensitive markers of hypercoagulability such as fibrinopeptide A, thrombin-antithrombin complexes, and prothrombin fragment F1 + 2.

In vitro inhibition of interferon alpha-2a antiproliferative activity by antibodies developed during treatment for essential thrombocythaemia

BACKGROUND

Various authors have reported the development of anti-interferon (IFN) antibodies following IFN-alpha treatment for haematological malignancies. So far the methods for detecting these antibodies have not considered the antiproliferative activity of this IFN, which is its most important property in anticancer therapy.

METHODS

In this in vitro study we evaluated the ability of anti-IFN alpha-2a neutralising antibodies to inhibit the antiproliferative activity of IFN alpha-2a and lymphoblastoid IFN alpha using megakaryocyte colony growth as the revelatory system. These antibodies were detected in two patients affected by essential thrombocythaemia (ET) who lost their haematological response to IFN alpha-2a, but responded to a subsequent treatment with lymphoblastoid IFN alpha.

RESULTS AND CONCLUSION

The results show that the inhibition of megakaryocyte colony growth induced by IFN alpha-2a was totally suppressed in the presence of the two ET patients' sera, whereas the inhibition induced by lymphoblastoid IFN alpha was not significantly affected. These in vitro data demonstrate the high specificity and activity of these antibodies on the antiproliferative effect of IFN alpha-2a.

Ascorbic acid for the treatment of chronic refractory idiopathic thrombocytopenic purpura (ITP)

We describe our experience with ascorbic acid in the treatment of chronic refractory ITP. Nine patients, 5 males and 4 females aged 27-74 years, 4 of whom were previously splenectomized, received the drug at a daily dose of 2 grams. After 2-12 months (median 4) of treatment, a partial response was observed in only one patient, while no response was registered in the other eight. Our data, analyzed together with those of the literature, allow us to conclude that ascorbic acid may not be considered a drug of interest in the treatment of chronic refractory ITP.

The risk of developing disease for siblings of patients with insulin dependent diabetes mellitus

We analyzed the risk of developing insulin-dependent diabetes mellitus (IDDM) in 411 siblings of patients with IDDM. We found that siblings who had a positive test for antibodies against islet cells (ICA) at the time of diagnosis of the index case had a higher risk of developing IDDM than did those who had negative tests. However, of the ten siblings who developed IDDM, only four were positive at the initial testing. The period of time elapsing from a negative test at screening to a positive test at diagnosis varied but was less than one year in one child. Two of the ten siblings who developed IDDM had negative tests both at screening and at diagnosis. Amongst siblings who were negative at the initial screening, those in whom the index case was diagnosed at a young age had a higher risk of developing IDDM than did those in whom the index case was diagnosed at an older age. The age of the sibling at the time of screening, the sex of the sibling, and a positive family history (one which includes in addition to the index case one or more first-degree relatives with IDDM) did not confer increased risk. Our data suggest that screening for ICA will have to be done often and will have to be continued into adult life in order to identify the 70-80% of diabetics who will be positive at some time in the evolution of their disease.

Essential thrombocythemia: impaired regulation of megakaryocyte progenitors

In this paper, the in vitro growth of bone marrow early (megakaryocyte burst-forming units, BFU-meg) and late (megakaryocyte colony-forming units, CFU-meg) progenitors was evaluated in 18 essential thrombocythemia (ET) patients and 22 normal control subjects. BFU-meg clonality was demonstrated both in normal and ET bone marrows, cultivating these primitive progenitors at limiting dilutions in plasma clot assay: 1 to 7 BFU-meg/2.5 x 10(4) mononuclear non-adherent cells were observed, with a strong correlation in ET [r = 0.955 stimulated by recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) plus recombinant human interleukin (rhIL) 3], as well as in normal controls (r = 0.969). In order to clearly elucidate the in vitro response of ET megakaryocyte (meg) progenitors to recombinant growth factors, the interference of accessory cells (i.e., monocytes, T lymphocytes, and natural killer cells) and human serum were avoided by performing experiments on CD34+ cells in a serum-free fibrin clot assay. The number of both early and late meg progenitors in ET was significantly increased in response to rhIL-3, rhIL-3 plus rhIL-6, and rhIL-3 plus rhGM-CSF, but not in response to rhGM-CSF alone. Furthermore, both meg progenitors were investigated for their response to rh transfer growth factor (TGF)-beta 1, tested at concentrations from 0.01 to 10 ng/ml. rhTGF-beta 1 was able to inhibit CFU-meg and BFU-meg in a dose-response manner normal, whereas ET CFU-meg appeared less sensitive to the lower doses investigated (p less than 0.05) and ET BFU-meg were slightly reduced in number only at the higher concentrations of rhTGF-beta 1 (p less than 0.01). Our data suggest that the increased thrombopoiesis in ET may depend on an increased sensitivity of meg progenitors to some of the physiological growth factors and to a disrupted sensitivity to at least one negative regulator of megakaryocytopoiesis. Since these abnormalities involve both meg progenitors, this can be considered a demonstration that the neoplastic event hits the most primitive hemopoietic progenitors.

Prompt plasma-exchange treatment and coma reversibility in two patients with thrombotic thrombocytopenic purpura

We report on the cases of two women with acute thrombotic thrombocytopenic purpura (TTP) whose clinical courses were characterized by the onset of a coma state. Prompt commencement of plasma-exchange (PE) treatment led to complete hematological and neurological remission, which can still be observed without any maintenance therapy. No CNS abnormalities were observed in either patient using brain CT and NMR scans.

Ticlopidine in the treatment of thrombotic thrombocytopenic purpura: report of two cases

The observation of two clinical cases make possible an evaluation of the potential therapeutic activity of platelet function inhibitors in thrombotic thrombocytopenic purpura (TTP). In particular, the clinical and hematological effects of ticlopidine (TC), employed alone in two TTP patients, are reported. The mechanism of action of this peculiar antiplatelet drug is mainly represented by the inhibition of fibrinogen binding on the platelet surface. In the first patient, a 45-year-old female in whom plasma-exchange (PE) and corticosteroids (C) led to a partial remission (platelets 80 x 10(9)/l), treatment with TC at a dose of 750 mg/day was carried out, and after 6 weeks a normal platelet count was observed. A complete remission was maintained for 31+ months, even after reduction of the TC dose to 250 mg/day. In the second patient, an 18-year-old female affected by relapsing TTP, a complete remission obtained with PE and C was maintained for 19 months in concomitance with TC treatment, started at a dose of 750 mg/day and lowered to 250 mg/day. After 11 months of treatment at this low dosage there was a relapse (platelets 20 x 10(9)/l), but the increase of the TC dose to 750 mg/day in a few weeks induced a complete remission again. These data, in accord with a few other recent preliminary reports, suggest that TC, even alone, may play an interesting role in the management of TTP patients.

Case-control study of IDDM

Insulin-dependent diabetes mellitus (IDDM) may be caused by a combination of genetic predisposition and environmental insults. However, there are few solid leads concerning human diabetogenic environmental agents. A case-control study was carried out to investigate the possible relationships between IDDM and various biological, chemical, and psychological factors. All 161 cases of IDDM among children aged 0-17 yr occurring in Montreal from 1983 to 1986 were included. The parent of each newly diagnosed diabetic subject was asked to provide the names of two of the child's friends or neighbors who would be age and sex matched to serve as controls. For those unable to do so, matched controls were selected from a hospital emergency room. Parents of cases and controls were interviewed concerning many factors. There was little or no difference between cases and controls with regard to parental smoking habits, exposure to pets, and consumption of meat products high in nitrosamines. In univariate analyses, there was some indication of elevated risk for children who had not been breast-fed, who attended day care or nursery before age 5 yr, who lived in a crowded household at age 3 yr, or who had a history of asthma or eczema, although in multivariate analyses the only variables that had any effect were crowding and day-care attendance. In univariate and multivariate analyses, there was high risk of IDDM among children who had experienced selected stressful life events during the 12 mo preceding onset of IDDM or who had exhibited symptoms of social or psychological dysfunction during that time.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo and in vitro inhibitory effect of alpha-interferon on megakaryocyte colony growth in essential thrombocythaemia

Megakaryocyte (MK) colony growth of bone marrow mononuclear non-adherent cells was evaluated in 28 patients with essential thrombocythaemia (ET) and in 26 normal controls. The number of MK-colony forming units (CFU-MK per 3 x 10(5) plated cells) was similar in ET (68 +/- 33) and in controls (63 +/- 37), independently of bone marrow accessory cells. On the contrary, the size of the MK colonies was significantly (P less than 0.01) greater in ET patients. Human recombinant alpha-interferon 2a (alpha-IFN), administered to 10 patients at a dose of 3 x 10(6) IU/d s.c. for 11 +/- 3 weeks, was capable of inducing a significant (P less than 0.01) decrease in the number (from 72 +/- 16 to 31 +/- 14) and size of bone marrow CFU-MK, together with a significant reduction of the platelet count (from 1031 +/- 325 to 378 +/- 75 x 10(9)/l). When added in vitro at time 0 to the culture dishes, alpha-IFN inhibited the CFU-MK growth of both normal and ET bone marrow samples, even at very low concentrations (1 and 10 IU/ml). This study demonstrates that alpha-IFN, both in vivo and in vitro, exerts an inhibitory effect on the growth of MK progenitors, which appears to correlate with the clinically documented antiproliferative effect of this cytokine.

Incidence of IDDM in Montreal by ethnic group and by social class and comparisons with ethnic groups living elsewhere

We examined the incidence of insulin-dependent diabetes mellitus (IDDM) among children aged 0-14 yr in Montreal by social class and by ethnic group from 1971 to 1985. There was a slightly higher risk in wealthier as opposed to poorer classes. This income gradient was more marked in younger than in older children. Children of French extraction had about two-thirds the risk of IDDM of children of other origins, mainly British and other European. This mimics the patterns of risk in Europe, where France is reported to have lower rates than does Britain and Scandinavia. The absolute levels of risks among French Canadian and Jewish Canadian children were about double those reported from France and Israel, respectively. These various results are compatible with the hypothesis that both genetic and environmental factors influence IDDM risk.

Impact of SMBG on control of diabetes as measured by HbA1. 3-yr survey of a juvenile IDDM clinic

Three hundred twelve diabetic children and adolescents were seen in our diabetic clinic and instructed to test their capillary blood glucose (CBG) twice daily and to use an algorithm to adjust their short-acting insulin. Of this group, 219 youngsters had a full 3-yr period of observation. At each clinic visit, blood was obtained for fasting blood glucose and HbA1 and, once a year, cholesterol and triglycerides were also measured. Patient and parent accuracy in measuring CBG was found to be adequate. The changes over time in HbA1 were nondifferential across age and sex, and there was no difference in the level of HbA1 between age and sex groups, the number of tests reported to have been done by the patients, the number of injections of insulin per day, or the serum cholesterol. There was a significant relationship between the HbA1 and the fasting blood glucose (P less than .001) measured by the laboratory as well as with the serum triglyceride (P less than .01). The failure to improve diabetic control, despite measures that would have been expected to do so, was believed to relate more to a lack of compliance than to a flaw in the therapeutic approach. It was interesting to note that the adolescent patients in the study were in no worse control than the younger children in the group. Although better technical skills are available today to manage diabetes, the psychosocial approach to patient motivation requires improvement.

The distribution of type I (insulin-dependent) diabetes mellitus by age, sex, secular trend, seasonality, time clusters, and space-time clusters: evidence from Montreal, 1971-1983

The etiology of insulin-dependent diabetes mellitus remains obscure. In an attempt to clarify some aspects of the epidemiology, including its compatibility with an acute infectious process, the authors undertook in-depth analyses of childhood cases accumulated in a population-based register in Montreal during the period from 1971-1983. Incidence rates increased with age until puberty, at which point they plateaued and decreased. There was no overall difference in incidence between males and females; however, the rate for females peaked approximately two years before the rate for males. While there was some variation over time, there was no evidence of a long-term trend, nor was the yearly variation impressive in magnitude. The findings further indicate that the disease is not characterized by explosive outbreaks. There was slight seasonality, with a 28% higher rate of onset in fall and winter than in spring and summer. There was some evidence of space-time clustering in 1971-1973, but not thereafter. Taken as a whole, these findings do not support the hypothesis that a significant portion of insulin-dependent diabetes is caused by an acute infectious process.

Intensified insulin therapy in the type I diabetic adolescent: a controlled trial

The effects of continuous subcutaneous insulin infusion (CSII), intensified conventional therapy (ICT), and a combination of CSII and ICT (CSII-ICT) on metabolic control were compared in a group of twenty type I diabetic adolescents who had previously failed to respond to twice-daily injections and home glucose monitoring. A marked improvement in control was observed when mean glycemia and glycosylated hemoglobin A1 (HbA1) were compared with conventional therapy (CT). In the course of CSII, a lower HbA1 (P less than 0.05) and mean capillary blood glucose (CBG) (P less than 0.04) were observed than during ICT and CSII-ICT. Acceptability of CSII was greater than that of ICT and CSII-ICT, with 50% of the patients opting for this therapy at the end of the 1-yr trial. The marked improvement of control observed under CSII for the group as a whole was maintained after 6 mo of completion of the study. Thus, it appears that in type I diabetic adolescents CSII is more effective and acceptable than ICT and CSII-ICT.

Feasibility of strict diabetes control in insulin-dependent diabetic adolescents

Nineteen insulin-dependent diabetic adolescents who had poor control on twice daily injections and home glucose monitoring participated in a study assessing the feasibility of improved control. Using a randomized crossover protocol, we examined the relative efficacy of continuous subcutaneous insulin infusion and of intensive conventional therapy with three or four daily injections of insulin. Both therapies were regulated with home glucose monitoring. A marked improvement in control with both therapies was observed when mean blood glucose and glycosylated hemoglobin A1 were compared with conventional therapy. However, pump therapy resulted in significantly lower HbA1 than intensive therapy (P less than 0.05), despite a significantly lower total insulin dose (P less than 0.01). We conclude that in adolescents with type I diabetes, continuous subcutaneous insulin infusion is more effective in achieving improvement of diabetes control than is intensive conventional therapy in the outpatient setting.

Comparison between continuous subcutaneous insulin infusion and multiple injections of insulin. A one-year prospective study

Twenty insulin-dependent diabetic patients participated in a 1-yr prospective randomized cross-over study comparing multiple subcutaneous injections (MSI) and continuous subcutaneous insulin infusion (CSII) complemented by home blood glucose monitoring. While 4 patients dropped out early, 16 patients completed the study. Patients had severe insulin deficiency documented by absent C-peptide response to glucagon stimulation. A marked improvement in control was observed when mean blood glucose and glycosylated hemoglobin A1 were compared with conventional therapy. No significant differences in the degree of metabolic control achieved, as measured by mean fasting, preprandial, and postprandial capillary blood glucose (CBG), M values, glycosylated hemoglobin A1 concentration, cholesterol and triglyceride levels were seen between MSI and CSII in the sixteen patients who completed the study. However, individual comparisons showed that fasting CBG and M-values were lower under CSII than MSI in seven patients (P less than 0.05). In contrast, two patients exhibited lower M values under MSI than under CSII (P less than 0.01), while for the remaining seven patients the results were similar. After completion of the study, two patients went back to conventional insulin therapy, seven patients remained on the pump, and seven patients chose to stay on MSI. In conclusion, on a long-term basis, the two methods can produce comparable levels of blood glucose and glycosylated hemoglobin in ambulatory insulin-dependent diabetics.

Prospective study of insulin-dependent diabetes mellitus

Laboratory study fo 109 insulin-dependent diabetics younger than 17 yr of age and resident in greater Montreal at the time on onset of symptoms is reported. The cases were diagnosed during a 2-yr period (1976-1978). Sibling controls were obtained for 72 of the cases studied. Viral titers to coxsackie B, rubella, and mumps virus for the 72 patient-sibling pairs showed no difference in geometric mean titers or in change of titer between samples taken at the time of diagnosis and those taken 28 days later. The incidence of positive islet cell antibody in teh IDdM cases was 68.0% at the time of diagnosis compared with 56.(% 4 wk later. The comparative figures of sibling controls were 4.2% and 1.4%, respectively. The frequency of HLA B8, B15, B18, and B7 antigens were compared both with the sibling controls and a normal control population. Pairing of high risk HLA antigens were found more frequently in cases than controls. There was no difference in geometric mean viral titers in cases with risk risk haplotypes compared with those cases in which such haplotypes were absent.

The problem of "cheating" in the diabetic child and adolescent

The frequency, causes, and consequences of "cheating" in diabetic children and adolescents were studied during summer camp. A philosophical approach is proposed for its understanding and management.

Insulin dependent diabetes: a comparison of families with single and multiple affected siblings

Families (n = 14) with more than 1 sibling with insulin dependent diabetes were matched with families of similar size and age distribution containing only 1 affected child. The distribution of HLA haplotypes, age of onset of disease, and seasonal onset of disease were compared in the two groups. The data are not consistent with the hypothesis of a single autosomal recessive gene linked to the HLA region. The data do not permit a choice between other current hypotheses although they are compatible with the theory of 2 genes linked to the HLA region, acting additively, and requiring interaction either with environmental factors or other disease susceptibility genes. Diabetic children in the multiplex and simplex families did not differ in the month of onset of symptoms nor in the age at diagnosis although three multiplex pedigrees in which diabetes developed in all affected children before the age of 6 years were identified.

Epidemiologic survey of juvenile-onset diabetes in Montreal

Active search of hospital records was used to survey insulin-dependent juvenile-onset diabetics younger than 17 years resident in General Montreal at the time of onset of symptoms during a seven-year period (1971-1977). A mean annual incidence of 8.8/100,000 was found with variation from year to year (5.8 to 10.3). Eighty percent were five years of age or more at time of diagnosis, and the increase with advancing age was similar to that seen in other studies including the somewhat earlier increase in incidence among females. Seasonal peaks were noted in some but not all years and were more marked in years of high incidence and among males. More cases occurred in areas of high socioeconomic level as measured by average family income. The estimated incidence among siblings of diabetics is 15 times the incidence in the general population. Ten percent of diabetics have a first degree relative who is insulin dependent.

Late effect of nocturnal mist tent therapy related to the severity of airway obstruction in children with cystic fibrosis

To evaluate the long-term effect of nocturnal mist tent therapy on the progression of airway obstruction in children with cystic fibrosis (CF) of varying severity, two matched groups each consisting of 24 children with CF were studied during 18 months on mist tent therapy and 18 months of therapy. The progression in airway obstruction was measured by change in serial measurements of maximal midexpiratory flow (MMEF), from which a regression equation of MMEF against time was obtained for each individual. Changes in MMEF value with or without therapy were compared in patients matched for severity of disease as indicated by initial MMEF values. For the group as a whole no differences were found in the progression of the airway obstruction whether the patients received mist tent therapy or not. This therapy failed to benefit any of the groups of children with CF who had early, moderate, or advanced airway obstruction as judged from their initial MMEF value. It is concluded that nocturnal mist tent therapy neither decreases airway obstruction nor prevents its progression in children with CF.

Juvenile diabetes mellitus, optic atrophy, sensory nerve deafness, and diabetes insipidus--a syndrome

Four patients with diabetes mellitus, optic atrophy, and high-frequency neurosensory hearing loss, two of whom also had diabetes insipidus, are described. The frequency of this syndrome among patients with juvenile diabetes appears to be between 1/148 and 1/175. Because of the progressive nature of the disabilities and the autosomal recessive mode of inheritance, careful monitoring of all juvenile diabetic patients for other signs of the syndrome is warranted.

Variability of NPH insulin preparations

In 1968-69 certain juvenile diabetics receiving NPH insulin began having pre-breakfast glucosuria and mid-morning hypoglycemic reactions. A mail survey of our clinic population and a study done at the Quebec camp for diabetic children in 1969 revealed that certain lot numbers were associated with poor control and that a change to new lot numbers or alternate insulin preparations resulted in better control. "Suspect" insulin preparations and non-suspect insulins were given to newly diagnosed diabetics, and plasma insulin and glucose levels were measured over a 24-hour period. The data confirmed that the "suspect" insulins were causing early hypoglycemia and failing to control hyperglycemia during the latter hours of the 24-hour period. The lower glucose levels were associated with higher plasma insulin levels. The "suspect" insulins were further found to have elevated levels of free insulin in the supernatant fluid.The requirements for quality control of modified insulin preparations are reviewed and suggestions are offered for their improvement.

Effect of intravenous tolbutamide in juvenile diabetes mellitus

Intravenous tolbutamide was administered to three groups of children with diabetes mellitus: (A) those with newly diagnosed disease, (B) those diabetic for less than two and one-half years, and (C) those diabetic for more than three years. Children in Groups A and B were found to respond to tolbutamide with a drop in blood glucose which differed from the response of normal children in that it was slow in onset and persisted throughout a three-hour period of observation. Children in Group C were unresponsive to tolbutamide. Children in Groups A and B showed an interference with the expected starvation-induced rise in nonesterified fatty acids over the period of observation, while children in Group C showed gradually increasing levels. The effect of tolbutamide on nonesterified fatty acids was less striking and showed more individual variation than did the effect on blood glucose. A few children with early diabetes mellitus developed hypoglycemia which appeared resistant to the usual counter-regulatory mechanisms. The fall in blood glucose was not accompanied by increased levels of insulin in peripheral blood.