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Biomedical subjects

R Laitinen

Publications and source records attributed to R Laitinen.

14 recordsLinked to original sources
PubMed1992

Tc-99m HMPAO labeled leukocytes superior to bone scan in the detection of osteomyelitis in children.

Seven children (aged 7 to 16 years) with confirmed osteomyelitis underwent imaging with Tc-99m HMPAO labeled leukocytes and with Tc-99m diphosphonates. The patients were scanned at 1/2 hour and at 3 hours. The scans were evaluated visually, and the lesion-to-normal bone ratios were quantitated. All the lesions on leukocyte scans and six out of seven lesions in bone scans were readily detectable 1/2 hour after injection of the radiopharmaceutical, but 3 hours is the better imaging time. In quantitative analysis, the lesion-to-normal bone ratio increased with leukocytes significantly higher than with the bone scans (P less than 0.05). When the scintigraphic findings were compared with surgical and radiologic results, the leukocyte images detected and localized lesions better than the bone scans. According to these preliminary results, Tc-99m HMPAO labeled leukocytes seem to offer a rapid and accurate method for detecting bone infections.

Adolescent↗
PubMed1992

Simple procedure for red blood cell labeling with Tc-99m HMPAO. Preliminary clinical results.

Clinical applications for Tc-99m HMPAO labeled red blood cells have not been previously reported. The authors describe a simple, aseptic, closed, one-step centrifugal procedure for red blood cell labeling with Tc-99m HMPAO and isolation from whole blood, and they report the preliminary results of using these labeled red blood cells to detect acute gastrointestinal bleeding in 11 patients. Whole blood was radiolabeled with Tc-99m HMPAO preparation and blood cells were separated by centrifugation (30 min, 200 g, 20 degrees C) using Polyprep density gradient medium. Red blood cells contained about 50% of the radioactivity. Four out of the 11 patients imaged with a gamma camera after reinjection of labeled autologous red blood cells showed abnormal accumulation, suggesting gastrointestinal bleeding that was verified at surgery and was at the site of abnormal activity in all cases. Image quality with Tc-99m HMPAO was comparable to that of Tc-99m pertechnetate labeled pretinned red blood cells. Tc-99m HMPAO can be used as a red blood cell labeler; however, its elution rate from red blood cells limits its applicability in some investigations.

Adult↗
PubMed1991

Scintigraphy with 99mTc-HMPAO labeled leukocytes in acute cholecystitis.

99mTc-HMPAO labeled leukocyte scanning was performed on 38 patients with clinically suspected acute cholecystitis (AC) to evaluate its diagnostic value. The typical finding was an increasing accumulation of the tracer in the gallbladder wall in a 4 hour series of scintigrams. Leukocyte scan was positive in 16 of 17 patients with surgically and histologically confirmed AC. There were no false-positive findings. The sensitivity, specificity, and accuracy of scintigraphy were 94, 100, and 96%, respectively. In 2 patients with acute acalculous cholecystitis true-positive findings were observed. Scintigraphy with 99mTc-HMPAO labeled leukocytes is a valuable new imaging method in AC.

Acute Disease↗
PubMed1991

Chronic prosthetic vascular graft infection visualized with technetium-99m-hexamethylpropyleneamine oxime-labeled leukocytes.

Technetium-99m-HMPAO labeled leukocytes demonstrated chronic femoro-femoral prosthetic vascular graft infection several times during an 18-mo period in a 77-yr-old man. The intensity and distribution of the uptake in the graft were fluctuating in different imaging occasions possibly indicating the strength and location of the infection. Gallium-67-citrate imaging showed negative results twice. The reason for negative 67Ga results remained obscure. The infected graft was removed and the patient did well 5 mo postoperatively.

Aged↗
PubMed1990

Zinc, copper, and sexual maturation in 9-18-year-old girls and boys.

The relationships between serum levels of zinc and copper and sexual maturation were analyzed in 2291 9-18-yr-old Finnish girls and boys. Development of public hair, breasts, and genitalia were used to grade maturation according to Tanner's classification. Serum zinc and sexual maturation were not related. However, 15- and 18-yr-old girls who had matured most slowly had low serum levels of zinc compared with their age mates. Thus, sexual maturation seems not to be affected by zinc deficiency in Finland; effects of zinc status on maturation in some minor groups cannot, however, be excluded. Serum copper levels were associated with age and sexual maturation, which complicates the drawing of conclusions about possible deficiencies.

Adolescent↗
PubMed1990

Tc-99m labeled leukocytes in imaging of patients with suspected acute abdominal inflammation.

One hundred patients with suspected acute abdominal inflammation were imaged at 0.5, 2-3, 4-6, and 24 hours after the administration of Tc-99m HMPAO labeled autologous leukocytes. Scan findings were retrospectively compared with final diagnosis, serum C-reactive protein (CRP), and antibiotic treatment. Clinical findings were confirmed with surgery, barium enema, or sigmoidoscopy in 61 patients, and diagnosis was based only on clinical findings in 13 patients. In 26 patients, symptoms subsided before a final diagnosis was made. Tc-99m leukocyte images were positive in 45 of the 61 patients with a confirmed diagnosis, including all patients with acute cholecystitis (N = 4) and inflammatory bowel disease (N = 8). They were also positive in nineteen out of 25 patients who had acute colonic diverticulitis and in 6 out of 7 who had intra-abdominal abscesses. Abnormal activity was found in patients with colonic carcinoma, small bowel infarction, and acute appendicitis. Abnormal activity was visualized in 0.5-hour images in all but one of the positive cases. With the exception of two postoperative cases, malignant lymphoma, and a liver abscess, a CRP level of greater than 75 mg/L was associated with positive image findings. Antibiotic treatment did not affect imaging findings. Imaging with Tc-99m labeled leukocytes appears to be valuable for detecting and localizing abdominal inflammation, and three-phase imaging during the first 4-6 hours is recommended. In some cases, 24-hour images may be useful for distinguishing small bowel from large bowel inflammation.

Abscess↗
PubMed1989

Serum zinc and copper: associations with cholesterol and triglyceride levels in children and adolescents. Cardiovascular risk in young Finns.

Associations among serum lipids (total cholesterol, LDL-cholesterol, HDL-cholesterol, and triglycerides) and levels of serum zinc (S-Zn), serum copper (S-Cu), and their ratio were analyzed in 3373 3-, 6-, 9-, 12-, 15-, and 18-year-old Finnish girls and boys. S-Zn was positively related to total cholesterol, HDL-cholesterol, and LDL-cholesterol; S-Cu related negatively to HDL-cholesterol. Obesity did not affect these relationships. The few exceptionally high lipid levels found were not associated with very low or high S-Zn or S-Cu. S-Zn and S-Cu were related to serum lipids; causality between the variables, however, remains to be studied.

Adolescent↗
PubMed1989

Zinc, copper, and growth status in children and adolescents.

The associations between serum zinc and copper concentrations and anthropometric variables in 3415 3-, 6-, 9-, 12-, 15-, and 18-y-old Finnish girls and boys were investigated to identify groups with low serum zinc or copper concentrations and retarded growth, possibly suggesting deficiencies. Serum zinc levels and height, wt, body mass index, and skinfold thickness were not strongly related. Serum copper levels were negatively correlated with height and positively with wt, body mass index, and skinfold thickness. These relationships were clearest in both sexes between the ages of 9 and 15 y. Height, wt, body mass index, and skinfold thickness in subjects with very low or high serum values were in agreement with the correlations between these anthropometric variables and serum levels. Groups with clear deficiencies of zinc or copper could not be identified. We conclude that copper levels especially are correlated with stature between the ages of 3 and 18 y. In addition, the results suggest that deficiency states affecting growth are not very likely in healthy Finnish children and adolescents.

Adolescent↗
PubMed1988

Hair zinc and copper: relationship to hair type and serum concentrations in children and adolescents.

The zinc and copper serum and hair concentrations of 691 3-18-y-old girls and boys previously determined as a part of the Multicentre Study of Atherosclerosis Precursors in Finnish Children and Adolescents were further analyzed in order to find a possible association between these two zinc and copper indices. The influence of hair color and the diameter of individual hair strands on hair concentrations were studied by the analysis of covariance. Hair color and serum zinc concentrations were found to be associated with hair zinc concentrations in boys. Such an association was not found for zinc and copper concentrations in girls. Hair vs serum concentrations in different age and hair color groups did not show however, a significant relationship either in copper or in zinc concentrations. The subjects with very low or high serum zinc or copper concentrations did not usually have extreme hair concentrations and vice versa. However, there were some subjects with low or high serum concentrations associated with low or high hair concentrations.

Adolescent↗
PubMed1988

Serum zinc and copper in relation to diet in 3- to 18-year old Finnish girls and boys.

Serum zinc (S-Zn) and copper (S-Cu) concentrations were measured and compared with data on dietary intakes of energy, protein, fat, carbohydrate, zinc, copper, phosphorus, calcium, iron, sucrose, vitamin C and dietary fibre, collected by means of the 48-h recall method in 1634 3-, 6-, 9-, 12-, 15- and 18-year old girls and boys. The intake of fibre was inversely related to S-Cu but not to S-Zn. None of the dietary components measured seemed to have a distinct negative effect on S-Zn, indicating that such factors were present at levels too low to affect S-Zn, or associated with factors favouring Zn bioavailability. Factors decreasing the bioavailability of Zn or Cu may especially affect adolescent girls whose average intakes of both Zn and Cu were low.

Adolescent↗
PubMed1985

Zinc and alpha-fetoprotein in amniotic fluid from early pregnancies with fetal malformations.

Zinc and alpha-fetoprotein concentrations were quantitated in second-trimester amniotic fluid from 111 normal pregnancies and 29 pregnancies with various fetal malformations. The zinc level varied between 0.3 and 4.0 mumol/L (median 1.3) in the normal samples and between 1.8 and 17.9 mumol/L (median 5.0) in cases with malformations. The level was above 2.5 times the normal median in 23 of the 29 (79%) gestations with the malformations. Amniotic fluid zinc and alpha-fetoprotein levels showed a positive correlation (r = 0.78), and the alpha-fetoprotein level was elevated in all gestations with fetal disorders and elevated zinc levels, as well as in five of the six cases with fetal defects but normal zinc concentrations. The elevation of zinc was more marked than that of alpha-fetoprotein in three cases of fetal malformations. Five samples were false positive on alpha-fetoprotein assay but contained normal zinc levels. Removal of alpha-fetoprotein from amniotic fluid had no effect on the zinc concentration, indicating that zinc is not bound to amniotic fluid alpha-fetoprotein.

Adult↗
PubMed1985

Pyrolysis products of PCBs.

Model compound studies which were previously done for impurities and environmental residues of chlorophenols and for wastes of chlorination processes were extended to the impurities and pyrolysis products of polychlorinated biphenyls (PCBs). Model compounds were commercial products or synthesized and their structures proven by spectroscopic methods. These models were used as analytical reference substances in GC/ECD and GC/MS studies of the pyrolyzed PCB samples. In addition to previously known neutral components like polychlorinated dibenzofurans (PCDFs), chlorophenolic substances, especially polychlorophenols (PCPs) and polychlorinated biphenylols (PCB-OHs) were observed as major pyrolysis products of PCBs. Capacitor fires are suggested to produce in many cases chlorophenols which are major toxic hazards to people.

Chromatography, Gas↗
PubMed1979

The effects of schedule of reinforcement on stimulus overselectivity in autistic children.

Recent research demonstrated that when autistic children are presented a discrimination task with multiple cues, they typically respond to an abnormally limited number, usually one, of the available cues. This phenomenon, termed "stimulus overselectivity," has been implicated as a possible basis for many of the behavioral deficits characteristic of autism. The present investigation was conducted to systemically analyze the effects of changing the schedules of reinforcement during discrimination training on subsequent stimulus overselectivity. Twelve autistic children were taught a discrimination involving multiple visual cues, with a CRF schedule of reinforcement. The children were then overtrained on either the same (CRF) schedule or on a partial (VR:3) reinforcement schedule. Subsequent overselectivity on single-cue test trials was then assessed. Results suggested that significantly less overselectivity occurred when the children were presented with the VR:3 reinforcement schedule during overtraining. These results are discussed in terms of variables influencing overselectivity and in terms of implications for designing treatment procedures for autistic children.

Adolescent↗