Flexible electrogoniometers: kinesiological advantages with respect to potentiometric goniometers

Unlike conventional potentiometric goniometers, flexible electrogoniometers do not suffer from any alignment problems with respect to the joint axis. We hypothesized that flexible goniometers provide more valid measurements in that they avoid some biomechanical pitfalls. With both devices simultaneously we measured the movements of dorsal flexion of the ankle and flexion of the knee in three healthy subjects. In the various subjects, this comparison showed that the flexible goniometers signalled ankle excursion greater by 19-40% with the foot remaining in neutral position or being simultaneously pronated, and lower by 10-21% with the foot being simultaneously supinated. At the knee the flexible goniometers signalled a flexion greater by 24-32%, with respect to potentiometric goniometers. Biomechanical considerations support the validity of records taken with flexible goniometers, potentiometric measures being biased by (a) multijoint, multiplane motions underlying foot dorsal flexion, and (b) multiaxis motion underlying knee flexion RELEVANCE: In measurements of angles between adjacent body segments, flexible goniometers should be preferred to potentiometric goniometers despite their higher cost. Flexible goniometers not only are more practical: more importantly, they provide a valid measure of relative orientations in one plane, regardless of the number and different concurrent motions of the underlying joints.

[Effect of GH/IGF-I deficiency on bone and collagen turnover in children and adults with GH deficiency]

Serum bone Gla protein (BGP), marker of osteoblastic function, carboxyterminal cross-linked telopeptide of type I collagen (ICTP), index of bone resorption, and aminoterminal propeptide of type III procollagen, marker of collagen synthesis, were evaluated in children with GH deficiency (GHD), in adults with childhood-onset GHD and in adults with acquired GHD in adultlife. In children with GHD, serum BGP (12.7 +/- 0.5 ng/ml), ICTP (8.5 +/- 0.9 ng/ml) and PIIINP (3.4 +/- 0.4 ng/ml) were significantly lower (p < 0.0001, p < 0.0001 and p < 0.001, respectively) than those observed in a sex and age matched control group (BGP:18.9 +/- 0.9 ng/ml, ICTP: 14.4 +/- 0.6 ng/ml, PIIINP: 6.7 +/- 0.7 ng/ml). In adults with childhood onsed GHD, BGP levels (3.7 +/- 0.4 ng/ml) were significantly lower (p < 0.0001) than those recorded in a sex and age matched control group (5.4 +/- 0.1 ng/ml), while ICTP (4.7 +/- 0.7 ng/ml) and PIIINP (3.7 +/- 0.5 ng/ml) levels were similar to those found in controls (ICTP: 4.1 +/- 0.3 ng/ml; PIIINP: 3.3 +/- 0.2 ng/ml). In adults with acquired GHD, serum BGP (5.3 +/- 0.4 ng/ml), ICTP (3.8 +/- 0.4 ng/ml) and PIIINP (3.6 +/- 0.3 ng/ml) levels were not significantly different from those recorded in controls (BGP: 5.4 +/- 0.1 ng/ml, ICTP: 4.1 +/- 0.3 ng/ml, PIIINP: 3.3 +/- 0.2 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Galanin infusion restores the blunted GH responses to GHRH administration during GH treatment in children with constitutional growth delay

GH responses to GHRH (in basal conditions), GHRH (after six months of recombinant GH therapy) and GHRH plus galanin administration (after GH therapy) were determined in six children with constitutional growth delay (CGD). Before treatment, GHRH administration caused a clear rise of GH levels (mean GH peak: 38.0 +/- 7.2 ng/ml); mean GH net incremental area under the curve/120 min (GH nAUC) was 2631.0 +/- 519.8 ng/ml/120 min. During GH treatment, both height velocity and IGF-I levels significantly increased from 4.3 +/- 0.1 cm/yr to 9.4 +/- 0.9 cm/yr (p < 0.001) and from 218.7 +/- 12.3 ng/ml to 328.0 +/- 28.2 ng/ml (p < 0.001), respectively. After 6 months of GH therapy, mean GH peak (21.7 +/- 2.2 ng/ml) and mean GH nAUC (847.7 +/- 109.8 ng/ml/120 min) after GHRH administration were significantly lower (p < 0.05) than in basal conditions. Galanin infusion (10 micrograms/kg/bw) was able to completely restore the reduced GH responsiveness to GHRH administration. In fact, mean GH peak and mean GH nAUC after GHRH plus galanin were similar to those recorded after basal GHRH administration (GH peak: 37.5 +/- 4.0 ng/ml; GH nAUC: 2279.8 +/- 430.5 ng/ml/120 min). In conclusion, this study shows that the reduction of pituitary responsiveness to GHRH administration during GH treatment is not dependent on the depletion of the promptly GH releasable pool, since somatotroph refractoriness to GHRH can be overriden by the concomitant administration of galanin.

Quadriceps and hand-grip strength in adults with childhood-onset growth hormone deficiency

The effects of chronic growth hormone (GH) deficiency on muscle size and strength of postural (quadriceps) and non-postural (hand-grip) muscle groups, as well as on vertical jump capacity, were evaluated in six adults with childhood-onset GH deficiency. Data obtained were compared to those recorded in an age-, sex- and exercise-matched healthy control group. Thigh muscle plus bone cross-sectional area (CSAM+B) of the dominant quadriceps was significantly lower (p < 0.001) than in controls, while the CSAM+B/(Body height)2 ratio was similar to that of controls. The maximum voluntary contraction (MVC) of the quadriceps of patients was significantly lower (p < 0.002) than in controls, while no differences existed in the quadriceps force expressed per unit area (MVC/CSA) between patients and controls. As far as hand-grip was concerned, the CSAM+B of the dominant forearm was significantly lower (p < 0.003) than in controls, while the CSAM+B/(Body height)2 ratio was no different. The hand-grip MVC of patients was significantly lower (p < 0.004) than in controls, while no differences existed in the MVC/CSA ratio. It is noteworthy also that no difference existed in the hand-grip to quadriceps MVC ratio of the two groups. Furthermore, no differences were found in the vertical jump capacity, because both delta Height and delta Height/Body weight of patients were not significantly different from those of controls. In conclusion, our study suggests that GH deficiency seems to reduce the size and strength of postural and non-postural muscle groups to the same extent.(ABSTRACT TRUNCATED AT 250 WORDS)

[Serum levels of the carboxyterminal telopeptide of type I collagen in patients with thyroid disorders]

Serum carboxyterminal cross-linked telopeptide of type I collagen (ICTP) levels, marker of bone resorption, were evaluated in 35 patients with hyperthyroidism (age range: 21-68 years) and in 35 with hypothyroidism (age range: 28-69 years). Data obtained were compared with those recorded in an age and sex matched control group. In patients with hyperthyroidism, serum ICTP levels were significantly higher than in controls (mean +/- SE: 9.1 +/- 0.7 vs 4.1 +/- 0.3 ng/ml; p < 0.0001). In patients with untreated hypothyroidism ICTP levels were significantly reduced (2.5 +/- 0.2 ng/ml, p < 0.0001); seven patients with hypothyroidism, evaluated after substitutive L-thyroxine treatment, showed a significant increase of ICTP levels (6th month: 5.9 +/- 0.7 ng/ml, p < 0.02). Taking into consideration all the data recorded in patients with both hyper- and hypothyroidism, serum ICTP levels were positively correlated with those of free T3 and free T4 and negatively correlated with those of TSH. In conclusion, our data show that repeated determinations of ICTP levels, which directly reflect the bone resorption activity, might be usefully employed in the evaluation of bone turnover in patients with thyroid disorders.

[The adult patient with a congenital GH deficiency. Cholesterol-lowering effects of therapy with biosynthetic GH]

In adults with childhood onset GH deficiency, serum total and LDL cholesterol levels were significantly higher (p < 0.05 and < 0.01, respectively), while serum HDL cholesterol levels were significantly lower (p < 0.05) than those recorded in an age and sex matched control group. These biochemical alterations determined the presence of a marked increase of coronary risk indexes (total/HDL cholesterol and LDL/HDL cholesterol) which were significantly higher (p < 0.0001) than in controls. Serum VLDL and triglycerides levels were similar to those found in controls. After recombinant GH treatment (0.5 IU/kg/week, sc), serum total and LDL cholesterol levels were significantly reduced, becoming similar to those recorded in controls after six months' therapy. Serum HDL cholesterol levels, which were slightly reduced after 3 months, significantly increased after 6 months of GH treatment, becoming similar to those recorded in controls; no significant modifications were observed in VLDL cholesterol and triglycerides levels during treatment. The coronary risk indexes fell during GH treatment, but still remained higher than in controls. On the basis of these promising data, it is tempting to speculate that more prolonged GH treatment might be able to ameliorate the risk for cardiovascular diseases in adults with GH deficiency. Although further additional studies with a larger number of patients are needed to confirm these preliminary observations, adults with GH deficiency should be recommended to take into great consideration the control of other risk factors involved in the genesis of coronary disease.

Growth hormone treatment in adults with GH deficiency: effects on new biochemical markers of bone and collagen turnover

Serum bone Gla protein (BGP) and bone alkaline phosphatase (B-AP), markers of bone formation, carboxyterminal cross-linked telopeptide of type I collagen (ICTP), marker of bone resorption, and aminoterminal propeptide of type III procollagen (PIIINP) levels, index of collagen synthesis, were determined in 8 adults (mean age +/- SE: 29.6 +/- 1.2 yr) with childhood onset GHD before and after 3 and 6 months of recombinant GH treatment (0.5 IU/kg/week). Before treatment, mean BGP (3.8 +/- .5 ng/ml) and B-AP (44.9 +/- 6.9 IU/L) were significantly (P < 0.001 and p < 0.05, respectively) lower than those recorded in normals (5.4 +/- 0.1 ng/ml and 61.8 +/- 1.9 IU/L, respectively), while serum ICTP and PIIINP levels were similar to those found in controls (ICTP: 4.7 +/- 0.8 vs 4.1 +/- 0.3 ng/ml; PIIINP: 3.7 +/- 0.6 vs 3.2 +/- 0.2 ng/ml). BGP and ICTP levels significantly (p < 0.005) increased after 3 (28.4 +/- 5.3 ng/ml and 17.5 +/- 2.8 ng/ml, respectively) and 6 months (25.1 +/- 5.0 ng/ml and 15.0 +/- 1.9 ng/ml, respectively) of recombinant GH treatment. B-AP levels significantly (p < 0.01) increased during the treatment (basal: 44.9 +/- 6.9 IU/L, 3rd month: 173.6 +/- 40 IU/L, 6th month: 194.4 +/- 40 IU/L), while non B-AP levels remained similar to those recorded in basal condition. Serum PIIINP levels significantly (p < 0.0001) rose up after 3 (12.5 +/- 1.4 ng/ml) and 6 months (10.2 +/- 0.8 ng/ml). Serum BGP and ICTP levels were directly (r = 0.85, p < 0.001; r = 0.53, p < 0.01) correlated with serum IGF-I levels.(ABSTRACT TRUNCATED AT 250 WORDS)

New markers of bone and collagen turnover in children and adults with growth hormone deficiency

Serum bone Gla protein (BGP), a marker of osteoblastic function, serum carboxyterminal cross-linked telopeptide of type I collagen (ICTP), a marker of bone resorption, and serum aminoterminal propeptide of type III procollagen (PIIINP) levels, an index of collagen synthesis, were determined in seven children and eight adults with congenital growth hormone deficiency (GHD). In children with GHD, serum BGP (mean +/- s.e.: 12.9 +/- 0.7 ng/ml), ICTP (8.3 +/- 1.3 ng/ml) and PIINP (3.5 +/- 0.5 ng/ml) levels were significantly lower (P < 0.001) than those recorded in normal children (BGP 18.9 +/- 0.8 ng/ml, ICTP 14.4 +/- 0.5 ng/ml and PIIINP 6.7 +/- 0.7 ng/ml). Total alkaline phosphatase (184.7 +/- 13.4 IU/l) and bone alkaline phosphatase (77.8 +/- 4.1 IU/l) levels were also significantly lower (P < 0.0001) than in controls (338.1 +/- 14.9 IU/l and 181.0 +/- 7.8 IU/l, respectively). Serum BGP, ICTP and PIIINP levels were not significantly correlated with height velocity values. In adults with GHD, mean BGP levels (3.8 +/- 0.3 ng/ml) were significantly lower (P < 0.0001) than those recorded in normals (5.4 +/- 0.1 ng/ml). On the contrary, serum ICTP levels were similar to those found in controls (patients: 4.7 +/- 0.8 ng/ml vs normals: 4.1 +/- 0.3 ng/ml), suggesting the presence of a normal resorption activity associated with a reduced osteoblastic function. This finding was also confirmed by the presence of reduced bone alkaline phosphatase levels (GHD: 44.9 +/- 6.9 IU/I vs controls: 58.3 +/- 2.0 IU/I; P<0.02), while the less specific total alkaline phosphatase levels (119.5 +/- 14.8 IU/I) were similar to those recorded in normal subjects (122.3 +/- 4.0 IU/I). Serum PIIINP levels (3.7 +/- 0.6 ng/ml) were similar to those recorded in normals (3.2 +/- 0.2 ng/ml), suggesting that in adulthood the collagen turnover is not negatively influenced by the chronic GHD. No significant correlations were found between BGP/ICTP/PIIINP and IGF-I levels. In conclusion, our data show that in children with GHD the lack of GH insulin-like growth factor-I (IGF-I) effects on bone and collagen turnover is associated with a significant reduction of bone turnover (low bone formation plus low bone resoRption) and collagen synthesis. On the contrary, adult GHD seems to exert less relevant effects on bone and collagen turnover, probably due to the fact that in adult life further hormones or local factors might partially counteract the negative consequences of chronic GH-IGF-I deficiency.

Plasma free fatty acids and serum insulin in subjects feeding at 12-hour intervals; effects of methionyl growth hormone and of acipimox, an inhibitor of lipolysis

In normal men, plasma free fatty acids (FFA) are influenced by feeding and by fasting; in addition, iv infusions of methionyl growth hormone (met-GH), so far performed during morning hours, induce an FFA rise that can be blocked by acipimox (ACX), a nicotinic acid analogue. The aims of the present study were to evaluate, in the absence of food interferences, the following aspects: i) Fasting FFA, glycerol, and insulin (IRI) in the morning and in the evening, and their response to met-GH ii) The effect of ACX and of a sustained release ACX formulation (ACX-SR) on fasting and met-GH induced lipolysis and on IRI levels. In a double blind study, 6 normal men received 50% cal at 09:30 h and 50% at 21:30 h; during placebo administrations FFA, glycerol, and IRI levels were lower at 06:30 h than at 18:30 h, and an iv met-GH infusion (160 ng/kg/min lasting 180 min) had a similar effect on FFA and on glycerol at 06:30 h and at 18:30 h. ACX-SR, administered at 21:30 h and 09:30 h, lowered FFA and glycerol in the morning as well as in the evening, and prevented met-GH induced lipolysis in the morning, but not in the evening.(ABSTRACT TRUNCATED AT 250 WORDS)

The growth hormone clamp technique: inhibition of growth hormone release by growth hormone occurs independently of free fatty acids

It has been suggested that growth hormone (GH) can inhibit its own release: in fact it has repeatedly been shown that an acute methionyl-GH (met-GH) infusion blocks the GH response to GH-releasing hormone (GHRH). However, met-GH infusions are accompanied by a significant increase of free fatty acids (FFA), which can block GH release. The aim of this study was to evaluate whether the inhibition of GH response to GHRH also occurs when lipolysis is pharmacologically blocked. Therefore, six normal subjects received GHRH, 50 micrograms intravenously (IV), after a 4-hour saline infusion and a 4-hour met-GH infusion (80 ng/kg/min, yielding a constant GH level of 33.6 +/- 4.63 micrograms/L), and GH release was evaluated during the following 2 hours. To prevent lipolysis, all subjects received on both occasions acipimox, an antilipolytic agent, 500 mg during the 6 hours before IV GHRH. GHRH induced a clear GH release during saline infusion (46.6 +/- 2.70 micrograms/L) and a scanty GH release during met-GH infusion (9.3 +/- 1.52 micrograms/L; P less than .01). Plasma levels of FFA, somatostatin, insulin-like growth factor I (IGF-I), and glucagon and serum insulin levels were unaffected, while blood glucose levels slightly decreased during saline infusion, but not during GH infusion. These data confirm that met-GH inhibits GHRH-induced GH release, and demonstrate that this inhibition is not mediated by FFA levels.