Clinical and laboratory features of homocystinuria

Classic homocystinuria is an autosomal recessive metabolic disease due to a cystathionine-beta-synthase deficiency with consequent blocking of homocysteine and serine condensation for producing cystathionine. The characteristic biochemical abnormalities in the blood and urine are: abnormal accumulation of methionine, abnormal presence of homocystine and low values of cystathionine, cysteine or cystine (disulfide of the cysteine). The most frequent clinical signs are: subluxation of the lenses, mental retardation of different degrees, long bones excessively lengthened, scoliosis, susceptibility to arterial and venous thromboembolism. The latter is frequent after surgery, and may be life-threatening. This disease must be differentiated from Marfan's syndrome via laboratory tests.

Characterization of erythrocyte adducin from the Milan hypertensive strain of rats

Previous studies showed that erythrocytes from the Milan hypertensive strain of rats (MHS) are smaller and have a faster Na-K cotransport when compared with their normotensive controls (MNS). These characteristics are determined within the stem cell, are genetically associated with hypertension and are similar to other renal tubular cell abnormalities more directly involved in the development of hypertension in MHS. The difference in volume is maintained in ghost membranes, while the difference in transport is abolished in inside-out vesicles. Ghosts and cytoskeletons contain a 105-kilodalton protein already characterized by immunoblotting. This protein has been identified with erythrocyte adducin by several criteria, including binding to calmodulin and protein kinase C, phosphorylation and full immunological cross-reactivity with human adducin. Since only MHS rats immunized with MNS erythrocyte cytoskeletons produce anti-adducin antibodies, we suggest an immunogenic structural difference in adducin from the two strains, and an involvement of this difference in the alteration of Na-K cotransport observed.

Bronchial reactivity in diabetic patients. Relationship to duration of diabetes and degree of glycemic control

Bronchial reactivity was studied via carbachol testing in 46 patients affected by type 1 diabetes mellitus and in 30 control subjects and via exercise testing in 55 diabetic patients and 60 control subjects. In all subjects, reactivity to skin allergen tests, the existence of atopic illnesses, and family history for these diseases were evaluated. Diabetic patients were less affected by asthma than control subjects, although their family history of atopy is greater. Bronchial reactivity, as expressed by the results of carbachol testing, was lower in diabetic patients than in control subjects. Furthermore, the duration of disease in diabetic patients was positively correlated with the results of carbachol testing. Reduced bronchial reactivity might be an indication of initial damage to the autonomic nervous system, which would thus appear to be both a complication and a protective factor.

Pelvic ultrasonography in girls with precocious puberty, congenital adrenal hyperplasia, obesity, or hirsutism

Real-time ultrasonography of the pelvic organs was performed on 151 girls with various complete and incomplete forms of precocious puberty, 20 girls with congenital adrenal hyperplasia, 20 with hirsutism, 18 with obesity, and 133 age-matched normal girls. Uterine and ovarian volumes were calculated and the ovarian morphologic picture was classified as homogeneous, nonhomogeneous (less than three small cystic areas), microcystic (four or more small cystic areas less than 9 mm in diameter), follicular (at least one cystic area greater than 9 mm), and macrocystic (large cystic area greater than 20 mm). Ultrasound imaging allowed an easy distinction between true precocious puberty and premature thelarche or idiopathic premature adrenarche. It was also helpful in the diagnosis of transient sexual precocity, although in these cases the differential diagnosis of precocious puberty can be difficult. In postmenarcheal patients with congenital adrenal hyperplasia, ultrasound study showed a low uterine volume and, frequently, a macrocyst in the ovary. In hirsute girls and in a few obese patients, ovaries had an increased volume and a microcystic structure, similar to those in polycystic ovary syndrome. Pelvic ultrasonography can be useful not only in diagnosing disorders in sexual development but also for greater understanding of the pathogenesis of these and other disorders.

The Milan hypertensive rat as a model for studying cation transport abnormality in genetic hypertension

Environmental factors, genetic polymorphisms, and different experimental designs have been the main impediments to evaluating a genetic association between cell membrane cation transport abnormalities and human essential or genetic hypertension. We review the results obtained in the Milan hypertensive strain of rats (MHS) and in its appropriate control normotensive strain (MNS) to illustrate our approach to defining the role of cation transport abnormality in a type of genetic hypertension. Before the development of a difference in blood pressure between the two strains, the comparison of kidney and erythrocyte functions showed that MHS had an increased glomerular filtration rate and urinary output, and lower plasma renin and urine osmolality. Kidney cross-transplantation between the strains showed that hypertension is transplanted with the kidney. Proximal tubular cell volume and sodium content were lower in MHS while sodium transport across the brush border membrane vesicles of MHS was faster. Erythrocytes in MHS were smaller and had lower sodium concentration, and Na+-K+ cotransport and passive permeability were faster. The differences in volume, sodium content, and Na+-K+ cotransport between erythrocytes of the two strains persisted after transplantation of bone marrow to irradiated F1 (MHS X MNS) hybrids. Moreover, in normal segregating F2 hybrid populations there was a positive correlation between blood pressure and Na+-K+ cotransport. These results suggest a genetic and functional link in MHS between cell membrane cation transport abnormalities and hypertension. Thus erythrocyte cell membrane may be used for approaching the problem of defining the genetically determined molecular mechanism underlying the development of a type of essential hypertension.

Growth and growth factors in diabetes mellitus

Growth of 79 children with diabetes was analysed at diagnosis and again after one to 10.7 years of treatment with insulin. Both sexes were tall at onset, whereas at the last observation boys alone showed significant growth retardation. Height standard deviation score (SDS), however, showed no significant fall either in 32 subjects reassessed after five years of disease or in 18 subjects examined at full stature. Skeletal maturity was not significantly impaired after treatment. Pubertal growth spurt was reduced, especially in girls and in subjects with onset of disease at or around puberty. We found no significant correlation between height and height velocity SDS and glycosylated haemoglobin values or secretion of growth hormone during the arginine test. Somatomedin C values were correlated with height velocity SDS in prepubertal boys. The results of this study suggest that there are interferences in the growth of children with diabetes but that they do not seem to have a significant influence on adult height.

Blood coagulation changes in homocystinuria: effects of pyridoxine and other specific therapy

The aim of this study was to investigate the blood coagulation changes in three patients with homocystinuria, in baseline condition and during therapy. At baseline, antithrombin III activity and factor VII levels were reduced in all three patients; antithrombin III protein and protein C antigen were also slightly lowered in one patient, and factor X in another. beta-Thromboglobulin, a measure of platelet activation, was increased in one case. During pyridoxine treatment, antithrombin III activity was rapidly restored to normal; factor VII increased and beta-thromboglobulin decreased. These data suggest that, in addition to platelet activation, abnormalities of blood clotting, and particularly reduction of antithrombin III, may play a role in the thrombotic tendency associated with homocystinuria. The nature of these clotting alterations is still uncertain, but their improvement during active metabolic treatment suggests that the defect in amino acid transsulfuration of homocystinuria may directly affect synthesis or activity of some liver-dependent clotting factors.

A renal abnormality in the Milan hypertensive strain of rats and in humans predisposed to essential hypertension

Many similarities in kidney-function abnormalities were found between hypertensive rats of the Milan strain (MHS) and young normotensive human subjects with hypertensive parents, compared with the appropriate controls. These similarities included an increased glomerular filtration rate, increased pressor effect of the kidney after transplantation, increased 24-h urinary output and lower plasma renin activity and urinary kallikrein. The isolated MHS kidney perfused in vitro with an artificial medium had a higher glomerular filtration rate, a higher urinary output, higher tubular sodium reabsorption and higher oxygen consumption than the kidney of control Milan normotensive rats (MNS). Further, reogenic sodium transport across brush border vesicles isolated from proximal tubular cells is faster in MHS than in MNS. Erythrocytes and proximal tubular cells of MHS have a lower volume and sodium content than those of MNS, while sodium transport is faster and the Ca2+-ATPase at Vmax is lower. This indicates that the 'genetic' cellular abnormality responsible for the renal-function abnormality and the hypertension is also present in erythrocytes. Thus these cells may be used to study the genetic cellular mechanisms of hypertension. Experiments with bone marrow transplantation and with F2 hybrids obtained by crossing the F1 (MHS X MNS) hybrids showed that the MHS erythrocyte abnormalities are genetically determined within the stem cells and are genetically associated with the hypertension. Since, in human hypertensives, there was a correlation between abnormal erythrocyte sodium transport and renal function, it is proposed that erythrocytes may be used in studying the cellular molecular mechanisms of hypertension.

Relationships between growth factors (somatomedin-C and growth hormone) and body development, metabolic control, and retinal changes in children and adolescents with IDDM

We used the radioimmunoassay (RIA) method to determine somatomedin-C (SmC) basal values in 59 diabetic children and adolescents (20 prepubertal and 39 pubertal subjects; age range 2.75-20.16 yr; duration of diabetes 0.08-15.83 yr) and in 274 control subjects. In comparing diabetic subjects with controls, we considered only those 50 diabetic subjects who were age matched with the controls, i.e., those not over 16 yr chronological age. SmC basal levels in pubertal diabetic patients were no different from those of pubertal age-matched control children, whereas in prepubertal diabetic patients SmC was significantly lower than in the respective control children (P less than .001). No correlation was found between the z score for SmC (i.e., the number of standard deviations each SmC level is from the age- and sex-normalized mean) and duration of disease, velocity standard deviation score, severity of fluoroangiographic retinal changes, basal C-peptide values and HbA1 levels. No differences were encountered in mean SmC and SmC z-score values in the separate groups of poorly, fairly, and well-controlled diabetic children, in the groups with and without residual pancreatic activity, and in the group with and without retinal changes. In 16 of the pubertal diabetics and in 15 pubertal controls, serum glucose, growth hormone (GH), and SmC concentrations were determined during the night. The integrated nocturnal secretion of SmC was no different in diabetics than in controls, whereas the integrated nocturnal secretion of GH was significantly (P less than .025) higher in diabetics than in controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell membrane abnormalities and genetic hypertension

Evidence indicates that an alteration in kidney function has a causal role in the pathogenesis of hypertension in the Milan hypertensive strain (MHS) rat. At the prehypertensive stage, these animals have increased glomerular filtration rate and 24-hour urinary output, whereas plasma renin activity and urinary kallikrein are lower. After transplantation, the MHS kidney increases the blood pressure of a normotensive recipient. Micropuncture experiments, where single nephron filtration rate, tubuloglomerular feedback, proximal tubular reabsorption, micro-pressures in tubuli, and interstitium and interstitial oncotic pressure were measured, suggest that the intrinsic ability of MHS proximal tubular epithelium to reabsorb solute and water is greater in prehypertensive MHS rats than in Milan normotensive strain (MNS) rats. Also rheogenic Na transport across the brush-border vesicles isolated from proximal tubular cells is faster. When erythrocytes and proximal tubular cells of MHS rats are compared to those of MNS rats, the former have smaller volume and Na content, whereas the Na transport is faster and the Ca ATPase at Vmax is lower. This indicates that the genetic cellular abnormality responsible for the renal functional abnormality and hypertension is also present in erythrocytes. Moreover, MHS erythrocyte abnormalities are genetically determined within the stem cells and are genetically associated with hypertension. Because a correlation was also found in human hypertension between erythrocyte Na transport abnormality and renal function, it is proposed that the erythrocyte may be used for studying the genetic molecular mechanisms of hypertension.

Genetic and experimental hypertension in the animal model-similarities and dissimilarities to the development of human hypertension

In this article, we present the results we have obtained from experimental and genetic models of human essential hypertension, in order to investigate those findings relevant to understanding the time course and the mechanisms underlying the human disease. With experiments on the renal artery constriction in the conscious dog, we have shown that a kidney lesion can produce a form of hypertension not different, in the established phase, from the essential one and that the onset of this form follows a phasic pattern during which the initial stages are crucial for understanding the mechanisms leading to hypertension. We also consider a rat model (MHS) that spontaneously develops a form of hypertension very similar to the human disease. In this model, we have demonstrated by a kidney cross-transplantation experiment and functional studies that the kidney is responsible for the rise in blood pressure and that the organ dysfunction is probably due to a primary abnormality in ion handling of the cell membrane. This cellular alteration, detected both in MHS erythrocytes and in their kidney proximal tubular cells, should be the cause for the higher rate of kidney Na+ reabsorption observed in the MHS. Comparing this animal model with, at least, a subgroup of humans prone to develop hypertension or already hypertensive, it is possible to detect a series of similarities in the kidney function, hormonal pattern, and cellular function of the two species that allows us to argue that the MHS is a suitable model from which to draw conclusions relevant to the pathogenesis of essential hypertension in some humans.

Can antigliadin antibody detect symptomless coeliac disease in children with short stature?

Duodenal biopsy and tests for antigliadin antibodies were done in 108 children with short stature unassociated with gastrointestinal symptoms. Other investigations for causes of growth failure were also carried out. In 88 patients, the cause of short stature could not be determined (group I). In 9 patients (8.3%) biopsy showed total villous atrophy, indicating probable coeliac disease (group II), while 7 patients had mild partial villous atrophy (group III). 4 patients (3.7%) had complete growth hormone deficiency. Antigliadin antibodies detected by immunofluorescence (IFL-AGA) were positive in 8 of the 9 group II patients. Symptomless coeliac disease is therefore a commoner cause of short stature than is hypopituitarism; by use of the IFL-AGA test it is possible to select patients for biopsy, thereby identifying most of the coeliac patients. If duodenal biopsies had been limited to IFL-AGA positive patients, 18 biopsies would have been carried out and coeliac disease would have been diagnosed in 8 of the 9 patients.

Differences in somatomedin-C between short-normal subjects and those of normal height

We evaluated basal somatomedin-C (SmC) levels in 98 subjects 2 to 16.6 years of age, with height less than 3rd centile (Tanner), and in 274 healthy controls 2 to 15.8 years, with height greater than 10th centile. Growth-retarded subjects were defined as short-normal when they had normal GH release (greater than 8 ng/ml) in at least one of three tests: arginine, L-dopa, and sleep. In control subjects, there was a significant positive correlation between SmC levels and chronologic age, bone age, and pubertal stage (pubic hair, breast or testicular volume). The same correlations were present in short-normal subjects, but SmC levels were significantly lower than in normal children. The percentage of subjects with very low SmC values (less than or equal to 0.25 IU/ml in those older than 6 years, and less than 0.1 IU/ml in those younger than 6 years) was higher in the short-normal group of children older than 6 years. In growth-retarded subjects, SmC values were significantly higher (P less than 0.005) in subjects with normal GH response in at least one of the two pharmacologic tests, compared with those with normal GH response only during sleep. We conclude that short-normal subjects have, on average, low SmC values, which might indicate insufficient GH release. Therefore, current criteria to define GH deficiency and children needing treatment may be too restrictive.

Pelvic ultrasonography in premenarcheal girls: relation to puberty and sex hormone concentrations

Real time ultrasonography of the pelvic organs was performed on 114 normal premenarcheal girls aged between 2 years and 13 years 11 months. Values were obtained for total uterine length, anteroposterior diameters of the corpus and cervix, corpus/cervix ratio, and uterine and ovarian volumes and the resultant data were grouped according to age. It was concluded that there is no change in uterine size until approximately 7 years of age. Then the uterus begins to enlarge, both in prepubertal girls, in whom this is an age related function, and in pubertal girls, whose uterine growth is influenced not only by age but also by size and, independently of these two factors, by oestradiol concentrations. The onset of a modification in uterine morphology with a greater enlargement of the corpus than the cervix is also seen at age 7 years. Ovarian maturation begins in the very first years of life and, even in pubertal girls, seems to be influenced by age only and not by hormonal stimuli.

Diabetes mellitus and skin diseases in childhood

The skin diseases observed in 41 children affected by type-1 diabetes and in 1,273 children unaffected by diabetes were compared to evaluate the dermatoses that are associated to type-1 diabetes. A high prevalence of vitiligo, psoriasis and herpes simplex infections was found in diabetics. These data are confirmed by statistical comparison.

Elastic modulus in young diabetic patients (ultrasound measurements of pulse wave velocity)

Aim of this study is to confirm the validity of non-invasive evaluation with Doppler C.W. in the study of arterial diseases and in the identification of pre-clinical arterial lesions. We studied twenty-eight children suffering from diabetes mellitus, and dependent on insulin and a control group composed of twenty-eight healthy persons. All subjects were studied using the methodology of the transit time for the determination of the elastic modulus of the lower limb arterial wall and results were analysed according to a statistical method. Although the groups were small, an increase in pulse wave velocity was noted in diabetic children and a significative correlation was found between the elastic modulus and duration of diabetes.