Gain-switched all-fiber laser with narrow bandwidth.

Gain-switching of a CW fiber laser is a simple and cost-effective approach to generate pulses using an all-fiber system. We report on the construction of a narrow bandwidth (below 0.1 nm) gain-switched fiber laser and optimize the pulse energy and pulse duration under this constraint. The extracted pulse energy is 20 µJ in a duration of 135 ns at 7 kHz. The bandwidth increases for a higher pump pulse energy and repetition rate, and this sets the limit of the output pulse energy. A single power amplifier is added to raise the peak power to the kW-level and the pulse energy to 230 µJ while keeping the bandwidth below 0.1 nm. This allows frequency doubling in a periodically poled lithium tantalate crystal with a reasonable conversion efficiency.

Internal biliary drainage, parenteral nutrition, and variation in the total parenteral nutrition feeding solutions: influence on the healing of colon anastomosis in jaundiced rats.

The influence of preoperative internal biliary drainage and various types of total parenteral nutrition (TPN) on the healing of a colon anastomosis in 50 jaundiced rats was investigated. Jaundice was induced by division and ligation of the common bile duct. After 5 days a colon anastomosis was made. Ten days thereafter the bursting pressure of the anastomosis was measured as an assessment of wound healing. Bursting pressures were significantly lower in jaundiced rats compared with a sham-operated nonjaundiced group. Preoperative internal biliary drainage significantly improved bursting pressure (p less than 0.001) as did preoperative TPN (p less than 0.001). In the second part of the study the influence of four different feeding solutions on the healing of a colon anastomosis was tested. Solutions with and without 20% fat emulsion and a solution with branched-chain amino acids were tested as well as glucose only. No significant differences were observed among these four groups on the parameters tested.

A prospective survey of risk factors in young adults with arterial occlusive disease.

Few studies have presented a thorough analysis of young adults with symptoms of arterial occlusive disease. To learn more about the possible risk factors of vascular disease playing a role in these young patients, we have reviewed all patients of 45 years of age and younger with symptoms of arterial occlusive disease who had been referred to our department between 1978 and 1987. Thirty-seven patients (28 males and 9 females) were included in the study. The mean age at which the first symptoms occurred was 34 years. Most patients presented with chronic arterial obliterations of the lower extremities (31/37, 84%). In addition, 4 patients showed signs of ischaemic heart disease. A strongly positive family history of arteriosclerosis was obtained from 13 patients (35%). Hypertension was present in 7 patients (19%), diabetes in three (8%) and nicotine abuse was found in 27 patients (73%). Fifty-four percent of the patients (20/37) had undergone vascular reconstructive surgery, 19% (7/37) underwent transluminal dilatation, and 3 had had subsequent treatment of newly developed lesions. For this study, all patients were recalled to the outpatient clinic. A complete case history was taken followed by a physical examination and ECG. Laboratory examinations were performed to analyse parameters of: (a) coagulation; (b) fibrinolysis; (c) fat- and (d) methionine metabolism. Clear-cut laboratory abnormalities were found in 33 patients (33/37, 89%). Coagulation parameters were abnormal in 11 patients (30%) (protein S deficiency: 3 pts). Fibrinolysis was impaired in 15 patients (40%).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of a high-protein diet in acid maltase deficiency.

The effects of a high-protein diet were studied in 5 adult cases of acid maltase deficiency. Measurements of muscle strength, pulmonary function and 3-methylhistidine excretion revealed no improvement consistently attributable to the diet.

Glutaric aciduria type II: treatment with riboflavine, carnitine and insulin.

A boy, now 22 months old, is described who presented at the age of 6 weeks with hypoglycaemic coma. The excretion pattern of organic acids in the urine was consistent with glutaric aciduria type II (GA II). A high energy diet low in fat and protein was given. Treatment with riboflavine resulted in an improvement of the metabolite profile, and the patient gained weight. However, a tendency to hypoglycaemia and severe hypotonia persisted. Due to muscle weakness, aggravated by infections, artificial ventilation was necessary during three periods. Serum carnitine level was low. Treatment with carnitine, started during the third period of artificial ventilation, led to some improvement of muscle strength, but he still could not breathe without support. Treatment with insulin, combined with further enrichment of the diet with glucose, resulted in an increase in muscular strength and in weight gain. Thirteen families with GA II have been described upto now. This is the first patient with a severe form of the disorder wo has survived the 1st year of life. Treatment and metabolic studies are presented.

[The excretion of N-acetyl-beta-D-glucosaminidase in the urine of children with urinary tract diseases]. / De uitscheiding van N-acetyl-beta-N-glucosaminidase in de urine van kinderen met afwijkingen van de urinewegen.

In 81 children without any urinary or kidney disease and in children with various diseases of the urinary tract, the excretion of N-acetyl-beta-D-glucosaminidase (NAG) was measured in an urine sample and related to creatinine excretion. The values of the first group of children accorded well with normal values reported in the literature. The age dependency (1-12 years) of the ratio NAG/creatinine is not of great importance, a single normal value for mean and mean + 2SD can be used. The estimation of NAG proved to be a relatively simple and useful measure of the involvement of the upper urinary tract in urinary infections. This is important for decisions about choice of treatment and further urological investigations.

Morquio-B disease, spondyloepiphyseal dysplasia associated with acid beta-galactosidase deficiency. Report of three cases in one family.

Two sisters and one brother, all with normal intelligence and no evidence of neurological abnormality, present progressive spondyloepiphyseal dysplasia, stunted growth, corneal opacities, and increased keratansulfaturia. Cultured skin fibroblasts from one of the children showed a remarkable deficiency of acid beta-galactosidase in association with normal activities of N-acetylgalactosamine-6-sulfate sulfatase and sialidase. Acid beta-galactosidase was also deficient in leukocytes of two children. Leukocytes of the parents exhibited intermediate activities, which suggests the primary nature of beta-galactosidase deficiency. Patients with MPS IV-B may be severely affected.

Genetic heterogeneity and clinical variability in the Sanfilippo syndrome (types A, B, and C).

A study of 73 patients with the Sanfilippo syndrome (36 patients with Sanfilippo A disease, 23 with Sanfilippo B disease and 14 with Sanfilippo C disease) revealed both intertype and intratype variability. The course of the disease was relatively mild in Sanfilippo B disease and dementia was less severe. Type A showed earlier onset with more severe clinical manifestations and an earlier age at death. Sanfilippo C disease was slightly less severe than Sanfilippo A disease. The intratype variability may be explained in part by differences in genetic and environmental background. In Sanfilippo B disease, genetic heterogeneity is suggested by the observation of a more severe and a mild variant, and this variation may be due to the involvement of different allelic mutations. The intrafamilial variability of the different types was small, but in three families with Sanfilippo B disease intrafamilial variability was evident.

A semi-quantitative micromethod for the determination of free glycosaminoglycans in serum. Results from studies on serum of healthy children of various age and patients affected by mucopolysaccharidosis.

A method is presented for the determination of free glycosaminoglycan (GAG) concentration in as little as 30 microliter serum. By filtration of the serum through DEAE-cellulose paper, the free GAG fraction is selectively adsorbed and concentrated on a circular area of 15.9 mm2; these GAG spots are stained with Alcian Blue. The relationship between the amounts of adsorbed GAG and the optical density of the Alcian Blue spots is linear with a certain range; e.g. for chondroitin sulfate (mixed isomers), from 0.25 to 1.00 micrograms. With this method--which we will refer to as the "DEAE Alcian Blue" method--we estimated the free GAG concentration in sera of individuals of various ages including newborns.

D-Lactic acidosis in a boy with short bowel syndrome.

Metabolic acidosis in a 3-year-old child with short bowel syndrome led to the discovery of massive D-lactic aciduria. After normalisation of the intestinal bacterial flora, D-lactate disappeared together with the acidosis. Dysbacteriosis with excessive production of D-lactate by intestinal bacteria (unidentified) and subsequent absorption explains this unusual cause of metabolic acidosis.

Hypoketosis as a cause of symptoms in childhood hypoglycemia.

Children with symptomatic hypoglycemia and asymptomatic hypoglycemia-prone children were shown to differ in the degree of ketosis after a 20 h fast. In the latter children the close negative correlation between ketone body levels and glucose levels yielded a regression line against which the former children's data could be compared. Half of the patients were found to be hypoketotic during hypoglycemia. The significance of this hypoketosis in the symptomatology is discussed. The finding of other abnormal responses to fasting, particularly in the patients' nitrogen metabolism, suggests that all these aberrations have a common cause which may be of hepatic origin.

Sanfilippo type C disease: clinical findings in four patients with a new variant of mucopolysaccharidosis III.

A new genetic variant of the Sanfilippo syndrome due to deficiency of acetyl CoA: alpha-glucosaminide N-acetyltransferase, was recently demonstrated in four patients. The clinical findings of these patients are reported here. Differential diagnosis from other types of the Sanfilippo syndrome on clinical and routine laboratory criteria is difficult and enzyme assay is necessary to reach the diagnosis. Since two of the patients reported are females and consanguinity was present in one case, autosomal recessive inheritance is most probable.

Sanfilippo B disease in two related sibships. Biochemical studies in patients, parents and sibs.

In two related Sanfilippo B families, comprising 27 individuals, some biochemical parameters were studied. After detection of the patients, an attempt was made to distinguish between heterozygotes and normals. The excretion of glycosaminoglycans in the urine and N-acetyl-alpha-D-glucosaminidase activity in leukocytes and plasma were taken as parameters for the study. The determination of N-acetyl-a-D-glucosaminidase activity in plasma is considered to be the most suitable method for heterozygote detection.