Tris(4-azidophenyl)methanol - a novel and multifunctional thiol protecting group

The novel tris(4-azidophenyl)methanol, a multifunctionalisable aryl azide, is reported. The aryl azide can be used as a protecting group for thiols in peptoid synthesis and can be cleaved under mild reaction conditions via a Staudinger reduction. Moreover, the easily accessible aryl azide can be functionalised via copper-catalysed cycloaddition reactions, providing additional opportunities for materials chemistry applications.

Macrocyclic Tetramers-Structural Investigation of Peptide-Peptoid Hybrids

Outstanding affinity and specificity are the main characteristics of peptides, rendering them interesting compounds for basic and medicinal research. However, their biological applicability is limited due to fast proteolytic degradation. The use of mimetic peptoids overcomes this disadvantage, though they lack stereochemical information at the α-carbon. Hybrids composed of amino acids and peptoid monomers combine the unique properties of both parent classes. Rigidification of the backbone increases the affinity towards various targets. However, only little is known about the spatial structure of such constrained hybrids. The determination of the three-dimensional structure is a key step for the identification of new targets as well as the rational design of bioactive compounds. Herein, we report the synthesis and the structural elucidation of novel tetrameric macrocycles. Measurements were taken in solid and solution states with the help of X-ray scattering and NMR spectroscopy. The investigations made will help to find diverse applications for this new, promising compound class.

High prevalence of osteoporotic vertebral fractures in patients with Crohn's disease

BACKGROUND AND AIMS

Osteopenia and osteoporosis are frequent in Crohn's disease. However, there are few data on related vertebral fractures. Therefore, we evaluated prospectively the prevalence of osteoporotic vertebral fractures in these patients.

METHODS

A total of 293 patients were screened with dual energy x ray absorptiometry of the lumbar spine (L1-L4) and proximal right femur. In 156 patients with lumbar osteopenia or osteoporosis (T score <-1), x ray examinations of the thoracic and lumbar spine were performed. Assessment of fractures included visual reading of x rays and quantitative morphometry of the vertebral bodies (T4-L4), analogous to the criteria of the European Vertebral Osteoporosis Study.

RESULTS

In 34 (21.8%; 18 female) of 156 Crohn's disease patients with reduced bone mineral density, 63 osteoporotic vertebral fractures (50 fx. (osteoporotic fracture with visible fracture line running into the vertebral body and/or change of outer shape) and 13 fxd. (osteoporotic fracture with change of outer shape but without visible fracture line)) were found, 50 fx. in 25 (16%, 15 female) patients and 13 fxd. in nine (5.8%, three female) patients. In four patients the fractures were clinically evident and associated with severe back pain. Approximately one third of patients with fractures were younger than 30 years. Lumbar bone mineral density was significantly reduced in patients with fractures compared with those without (T score -2.50 (0.88) v -2.07 (0.66); p<0.025) but not at the hip (-2.0 (1.1) v -1.81 (0.87); p=0.38). In subgroups analyses, no significant differences were observed.

CONCLUSIONS

In patients with Crohn's disease and reduced bone mineral density, the prevalence of vertebral fractures-that is, manifest osteoporosis-was strikingly high at 22%, even in those aged less than 30 years, a problem deserving further clinical attention.

[Hormonal "rejuvenation". Warning your patients from false claims!]

No intervention, including drugs and hormones, has been proven to slow or even reverse aging. Such promises, as well as the term "anti-aging medicine", are misleading. On the other hand, remarkable progress has been made in the prevention and treatment of age-related diseases. The use of hormones constitutes a potentially new option in the prevention and treatment of age-related diseases, but is not an established therapy. The status of scientific evidence for the treatment of seniors with growth hormone, melatonin, DHEA or testosterone is critically reviewed.

Increase of bone mineral density with sodium fluoride in patients with Crohn's disease

BACKGROUND AND AIMS

Low bone density with an increased risk of vertebral fractures is a frequent complication in inflammatory bowel disease. Since the aetiology of osteopathia in these patients is different compared to postmenopausal or steroid-induced osteoporosis, no treatment strategy is established. Supplementation of calcium and vitamin D has been shown to prevent further bone loss, but no data are available showing the anabolic effect of sodium fluoride in Crohn's disease.

METHODS

We carried out a one-year prospective clinical trial in 33 patients with chronic active Crohn's disease who were randomly assigned to receive either calcium (500 mg b.i.d.) and 1000 IU vitamin D3 only, or retarded-release sodium fluoride (25 mg t.i.d.) additionally. The diagnosis of Crohn's disease had been made at least two years ago, and all patients had received systemic high-dose steroid therapy during the previous year. Eleven of 15 patients who received calcium/vitamin D and 15 of 18 patients who additionally received sodium fluoride completed the study. The primary endpoint of the study was the increase of bone mineral density, measured by dual energy X-ray absorptiometry (DXA) after one year of treatment. Bone-specific alkaline phosphatase and osteocalcin were used as markers for bone turnover.

RESULTS

In the calcium/vitamin D only group, bone density was not significantly changed after one year of treatment, whereas in the calcium/vitamin D/fluoride group, bone density of the lumbar spine increased from -1.39+/-0.3 (Z-score, mean +/- SEM) to -0.65+/-0.3 (P<0.05) after one year of treatment. Increase of bone density was positively correlated to the osteoblastic markers bone-specific alkaline phosphatase (r = 0.53) and osteocalcin (r = 0.43).

CONCLUSIONS

Sodium fluoride in combination with vitamin D and calcium is an effective, well-tolerated and inexpensive treatment to increase lumbar bone density in patients with chronic active Crohn's disease and osteoporosis.

[ABC of osteoporosis therapy. Which drugs for prevention and therapy?]

Medical Prevention and Therapy Fractures in the elderly, in particular of the proximal femur, may give rise to functional impairment with loss of independence and mobility. Apart from falls, the most common cause of fractures is osteoporosis or other impairments of mechanical stability of bone. In addition to the avoidance of falls and their sequelae, and the minimization of risk factors where possible, optimization of the mechanical stability of the bone is an important point of attack for interventional strategies. Current data on medical possibilities of osteoporosis prevention and treatment are presented and evidence for their effectiveness in reducing fractures discussed. Recommendations based on confirmed data are made, and possible future therapeutic approaches discussed.

[Pathological bone density in chronic inflammatory bowel diseases--prevalence and risk factors]

INTRODUCTION

Osteopenia and osteoporosis are frequent but often underestimated complications in inflammatory bowel disease. In patients with IBD, several factors could contribute to osteopenia, but the pathogenetic mechanisms are still not completely understood. We carried out a prospective study to evaluate the prevalence and possible etiologic factors for osteopenia and subsequent osteoporosis in IBD-patients.

METHODS

140 patients with inflammatory bowel disease (Crohn's disease n = 125, ulcerative colitis n = 15) underwent clinical and spine radiological assessments. Lumbar bone mineral densities were measured by dual energy X-ray absorptiometry (DXA). Markers of bone formation and resorption and vitamin D were assessed in n = 95 patients. Patients were asked about medication, previous or actual intestinal stenosis, smoking and intestinal resection. A lactose-H2-breath test was undertaken if lactose intolerance was clinically suspected.

RESULTS

Compared to age- and sex-matched healthy controls (Z-score), the prevalence of osteopenia (Z < -1) was 62%, while osteoporosis (Z < -2) occurred in 38%. The mean bone density of IBD-patients was osteopenic with no significant differences between Crohn's disease (Z = -1.24) and ulcerative colitis (Z = -1.25). Osteoporotic fractures were seen in three patients (2.1%). Crohn's disease patients with osteoporosis showed a significant lower body mass index (BMI) than patients with normal bone density. 52.9% of patients with manifest osteoporosis underwent systemic steroid treatment in the preceding year, but only 34% of those with normal bone density. Except hemoglobin, none of the biochemical markers showed a significant difference between osteoporosis, osteopenia and patients with normal bone density.

CONCLUSION

The results show a high prevalence of osteopenia and osteoporosis in IBD. Since osteoporosis is often associated with low body mass index, multiple intestinal resections and previous systemic steroid treatment, we suggest a bone densitometry in these patients. Since etiology of osteoporosis in IBD is multifactorious and not completely understood, there is still no standard treatment. The effect of osteoanabolic and antiresorptive agents must be evaluated in further studies.

Prevalence of Helicobacter pylori infection and dyspepsia in young adults in Germany

Data on the seroprevalence and time of acquisition of Helicobacter pylori (HP) infection in Germany are scarce. We studied the seroprevalence of HP infection and the relationship with gastrointestinal (Gl) symptoms in a group of 168 German medical students in the final year of their practical training and in 260 age-matched blood donors at the University of Ulm. Eight upper Gl symptoms were scored in a questionnaire, and blood samples were taken for the detection of HP lgG antibodies with an Enzyme Immunoassay (Bio-Rad). Values greater than 12.5 U/ml (positive) were detected in 50 medical students (28.8%) and in 96 blood donors (36.9%). At least one occasional Gl symptom was present in 71.4% of medical students and 70.7% of blood donors. When related to the HP status, 27.0% of HP negative and 32.9% of HP positive individuals were completely free of symptoms. Moderate to severe dyspeptic symptoms were reported by 17.4% of HP negative and 14.4% of HP positive individuals. We conclude that the seroprevalence of HP infection in young German adults is presently about 1/3 but that HP infection is not linked to gastrointestinal symptoms in this age class.

[Development and outcome of motivational support during inpatient education of insulin-dependent diabetic patients--a pilot project]

At the Ulm University Hospital 43 type-1-diabetes patients took part in a structured in-patient diabetes education program during a 12-day hospitalization period. 27 of the patients received an additional motivational support program which addressed psychological and social impediments related to the topics of the structured diabetes education program. 16 patients underwent the structured diabetes education program only. Motivational support aimed at reducing the specifically addressed sociopsychological barriers. Thus, the effects of the structured diabetes education program should be stabilized and an optimal outcome insured. All patients were asked to complete a questionnaire before, right after and 3 months after the program. Glycosylated hemoglobin (HbAlc) was evaluated before and 3 months after the program. Patients who underwent the motivational support program still felt 3 months after completion of the program that metabolic control was important, whereas patients without motivational support did not. Metabolic control--as indicated by measurement of glycosylated hemoglobin--could be maintained in the patient group with motivational support. Although their blood glucose levels had been in the normal range to start with. These encouraging results suggest implementation of a motivational support program into standard diabetes education programs for type-I-diabetes patients.

Progress in practical endocrinology. The Glucosensor Unitec Ulm--a portable monitor for continuous blood glucose measurement

The Glucosensor Unitec Ulm is the first portable glucose sensor for continuous glucose monitoring in blood. The Glucosensor weighs 850 g and has a size of 15 x 19 x 7 cm. Over a 24 hr period 15-25 ml of blood are withdrawn for continuous measurement, depending on the pumping velocity. Its storing capacity for data of blood glucose readings amounts to 32 KB. With the Glucosensor "long-term glucograms" under near-normal conditions can be registered. The glucograms enable the physician to recognize the different deteriorations of glucose met- abolism eg. periods of silent hypoglycemia during the night as well as postprandial hyperglycemia. The degree of glycemic control of diabetic patients can be analyzed and the effect of blood glucose lowering therapeutics can be realistically assessed.

["Glucosensor Unitec Ulm". A portable, continuously measuring glucose sensor and monitor]

The "Glucosensor Unitec Ulm" is the first commercially available, portable glucose monitor that permits continuous measurement in venous blood under ambulatory conditions for up to 256 hours. The device weights 850 g, and measures 15 x 19 x 7 cm. Depending on the flow rate of the pump, the blood requirement is 15-25 ml/24 h. The size of the built-in-memory is 32 kByte, enough to store 3180-15,900 glucose values. The "24 hour glucogram" obtained under day to day living conditions permits the detection of disturbances of carbohydrate metabolism. Thus, early abnormalities of type II diabetes can be detected as well the degree of blood glucose normalization in patients suffering from severe insulin-dependent diabetes. Moreover, the effects of glucose-lowering drugs can be analyzed objectively. Finally, this portable glucose monitor permits the recognition of hypoglycemia induced by insulin administration or endogenous insulin overproduction due to tumors.

In vivo measurement of subcutaneous glucose concentrations with an enzymatic glucose sensor and a wick method

An amperometric enzyme electrode and a wick technique were used for measurement of glucose in sc. tissue of sheep. When wicks were left implanted long enough to equilibrate with interstitial fluid, sc. glucose could have been reproducibly determined with the necessary accuracy. It was demonstrated that sc. tissue glucose concentrations in sheep are about 30% higher than in whole blood and are on the level of plasma glucose. This allows interpretation of sc. glucose sensor currents since results of in vitro-calibrations cannot be transferred to in vivo conditions. When an enzymatic sensor was implanted in the sc. compartment, the sensor signals were closely related to changes of blood glucose. These in vivo experiments indicate that short term glucose-monitoring with an subcutaneously implantable glucose sensor is feasible and so may provide a possible access to glycemic control. Further experiments will have to show, if glucose-controlled insulin infusions based on the output of a sc. glucose sensor will be able to maintain stable normoglycemia.

Similar effects of pulsatile and constant intravenous insulin delivery

Effects of constant and pulsatile i.v. insulin delivery were examined in seven healthy subjects by means of euglycemic clamp technique. Each subject received constant insulin infusion (0.175 mU/kg.min) or insulin pulses at 12-min intervals (2.1 mU/kg) in randomized order for 8-h periods (08.00-16.00 h). Endogenous secretion of insulin was inhibited by concomitant administration of somatostatin (300 micrograms/h). Serum insulin concentrations during constant infusion (12 +/- 1 microU/ml) did not differ from basal values (11 +/- 1 microU/ml). Pulsatile insulin delivery resulted in oscillations of mean concentrations between values of about 10 and 20 microU/ml. Mean blood glucose concentrations during experiments were kept at 80 +/- 1 mg/dl, irrespective of the mode of insulin administration. Moreover, dextrose requirements for maintenance of these glucose concentrations did not differ over the hole periods of examination. We conclude that effects of constant and pulsatile delivery of basal amounts of insulin are not different. This at least applies to peripheral, short-term insulin administration in somatostatin-treated normal man, during an euglycemic clamp.