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Biomedical subjects

H R Ham

Publications and source records attributed to H R Ham.

At least 91 records · Page 5Linked to original sources
PubMed1989

Per rectal thallium scintigraphy for the assessment of portosystemic shunt: an experimental study in the bile duct ligated rats.

Bile duct ligated rats (n = 7) have been investigated for 6 months. Two patterns of evolution have been observed: (i) progressive development of cirrhosis and portosystemic shunt (detected by 201Tl per rectal scintigraphy) in three animals, (ii) repermeabilization of the biliary tract in four animals. Despite the small number of animals investigated, the 201Tl per rectal scintigraphy seems to be a good indicator of portosystemic shunt secondary to biliary cirrhosis.

Administration, Rectal↗
PubMed1989

Muscular injury in a child diagnosed by 99mTc-MDP bone scan.

An 11-year-old boy had bone scanning to rule out an osseous lesion of the right arm. He presented progressive pain and hard swelling of the right arm. His past medical history and general physical examination were unremarkable. He trained for karate. The scan demonstrated considerable muscular uptake in both arms. CPK and CPK MB levels were both abnormally high, suggesting muscle injury. After a 10-day rest period the bone scan returned to normal.

Arm Injuries↗
PubMed1989

Prospective management of neonates with pelviureteric junction stenosis. Therapeutic strategy based on 99m Tc-DPTA studies.

A prospective therapeutic strategy based on separate glomerular filtration rate (SGFR) was evaluated in 14 prenatally detected asymptomatic neonates, suspected of having pelviureteric junction obstruction. The patients with low SGFR were referred for pyeloplasty with the hope to improve the renal function. A marked improvement occurred in only one patient, although the drainage function (furosemide test) did improve in all cases. A conservative attitude was adopted for those children with normal SGFR. In 6 of them, a progressive increase of SGFR was noted, related to the normal maturation of the function, followed by a stabilization in the normal range. In 1 patient, a sudden decrease of SGFR was observed around 1 year and the patient was shifted into the surgical group. In this patient, an initial partial response of the kidney to a furosemide injection changed into a persistent non-response, whereas in the other non-operated patients, partial or good response was always recorded, although the responses were essentially variable on successive tests. On the basis of these data, the protocol was slightly modified, the patients with persistent non-response to furosemide after 6 months of life being shifted to the surgical group.

Clinical Protocols↗
PubMed1989

Continuous anterior acquisitions in gastric emptying: comparison with the mean.

Depth correction is necessary when gastric emptying is studied by means of a labeled meal. In this study continuous anterior images were acquired from the onset of the food ingestion. Differences in depth were measured using a left lateral view. A minimal and crude depth correction was performed. The results obtained with this correction method were compared with those obtained using the depth correction technique of the mean. The results obtained in the anterior projection without any depth correction were also compared with those obtained using the method of the mean. The results obtained with both correction techniques were identical in 18 gastric emptying studies. This approach also permits the creation of a time-activity curve over the duodenum in the anterior projection. In this way the lag phase can easily be assessed.

Adult↗
PubMed1989

Evaluation of oesophageal transit in patients with minor peptic oesophagitis.

Fifty-one adult patients with complaints suggesting peptic oesophagitis were submitted within the same week to a radionuclide swallow test (OT), an endoscopy and a manometry in order to evaluate the incidence of oesophageal peristaltic abnormalities in patients with only minor peptic oesophagitis. In all patients with normal endoscopy, OT did not show any transit abnormality. In the patients with slight (Stage I) or moderate (Stage II) oesophagitis, OT was abnormal in 60% of the cases. The results were at least as good as those obtained by means of manometry and suggest that OT is an accurate method for the detection of slight impairment of oesophageal contractility.

Adult↗
PubMed1989

Reproducibility of quantitative 99Tcm-MAG 3 measurements in rats.

Repetitive quantitative renal extraction studies of 99Tcm-MAG 3, performed in nine rats, demonstrated excellent reproducibility of successive measurements. These results are better than with 99Tcm-DTPA, due to the higher renal extraction of the 99Tcm-MAG 3. The % of renal uptake 10 min after the injection was not influenced by the elapsed time between the end of the 99Tcm-MAG 3 preparation and its i.v. administration.

Animals↗
PubMed1989

Functional imaging of brain maturation in humans using iodine-123 iodoamphetamine and SPECT.

The application of regional cerebral blood flow (rCBF) study by means of lipophilic radiotracers and single photon emission computed (SPECT) devices in very young infants is hampered by the considerable changes of rCBF pattern as a result of the cerebral maturation process. In an attempt to determine the normal evolution of [123I]IMP SPECT pattern as a function of age, we retrospectively selected the studies of 30 babies with normal clinical examination, EEG and CT or ultrasound scans at time of SPECT. There was a marked predominance of the thalamic perfusion over cortical areas until the end of the second month. The distribution of regional cortical activity followed a strict sequence. The perfusion of both parietal and occipital areas was well-visualized around the 40th week of gestational age and thereafter rapidly rose, always, however, with a slight predominance of the parietal activity. At the opposite, frontal activity which remained scarcely recognizable up to the second month tremendously rose to present the adult-like pattern at the beginning of the second year. The rCBF changes described above are well in agreement with the behavioral evolution occurring during prime infancy.

Amphetamines↗
PubMed1989

Clinical usefulness of ultrashort-lived iridium-191m from a carbon-based generator system for the evaluation of the left ventricular function.

Ultrashort-lived 191mIr (4.96 sec; 63-74 and 129 keV photons) is potentially advantageous for first-pass radionuclide angiocardiography, offering the opportunity to perform repeat studies with very low absorbed radiation dose to the patient. Left ventricular (LV) first-pass studies were performed in 72 patients with 191mIr from a new bedside 1.3 Ci (48.1 GBq) 191Os/191mIr generator system using an activated carbon support that offers high 191mIr yields (15-18%) and consistent low 191Os breakthrough (2-4 x 10(-4)%/bolus). Using a single crystal digital gamma camera, uncorrected end-diastolic counts in the left ventricular representative cycle ranged from 10 up to 30 k counts. The reproducibility of repeated LV ejection fraction (LVEF) determination at 2-min intervals in 50 patients was r = 0.97, mean diff. = 2.08 +/- 1.55 EF units. Comparison between 191mIr (80-120 mCi; 2,960-4,400 MBq) and 99mTc (20-25 mCi; 750-925 MBq) LV count rates indicates a 3 wk useful shelf life of this new generator system for cardiac studies. Iridium-191m determined LVEF correlated closely with 99mTc determined LVEF in 32 patients (r = 0.96, mean diff. = 1.87 +/- 1.23 EF units). Parametric images for LV wall motion analysis were comparable with both isotopes. We conclude that rapid, repeat, and reproducible high count rate first-pass left ventricular studies can be obtained with 191mIr from this new 191Os/191mIr generator system using a single crystal digital gamma camera.

Adult↗
PubMed1988

Assessment of vertebral mineral content by means of a single-crystal scintillation camera.

Increasing interest in bone mass has led to dedicated commercial dual photon absorptiometry (DPA) instruments. We describe a method for the measurement of the mineral content of the lumbar spine using a scintillation camera. The most appropriate source(s) and collimator were investigated. An especially constructed arm placed the sources in the focal point of a converging collimator. Two single-peak sources, 99Tcm and 241Am, were used instead of dual-peak 153Gd source. Phantom studies showed no degradation of the results in water depths of up to 26 cm. Acquiring 10 Mcounts per image over a 300 cm2 field, a coefficient of variation (c.v.) of 1.7% was obtained. Reducing the total counts per image to 1 Mcount gave rise to a c.v. of 6.2%. Long-term measurements showed a c.v. of 1.1% for density, with a mean value of 0.98 gHa cm-2 compared to 0.90 for a commercial DPA instrument. Repeated measurements of the lumbar spine on 10 patients with a 2 week interval showed a c.v. of 5%. Comparative measurements were made between the scintillation camera and a commercial DPA instrument on six volunteers. Systematic higher results, similar to those observed with the phantom, were obtained with the scintillation camera. The reproducibility on a phantom and in patients is in the same range as commercial DPA instruments. The low cost related to the use of standard nuclear medicine equipment and to inexpensive radioactive sources represent definite advantages.

Humans↗
PubMed1988

Long-term follow-up of separate glomerular filtration rate in partially obstructed kidneys. Experimental study.

An often encountered assumption is that non-relieved renal obstruction will lead soon or late to progressive deterioration of the renal function. The effect of non-relieved partial ureteral obstruction on the separate glomerular filtration rate (SGFR) was studied throughout the whole life of a series of rats, who were submitted at the age of 3 months to partial obstruction of the left ureter. An initial and variable postoperative SGFR decrease was gradually observed, but after this period, SGFR remained stable until the natural death of the animal.

Animals↗
PubMed1987

Abnormalities of esophageal transit in patients with sporadic nontoxic goitre.

Esophageal transit (E.T.) was investigated in 122 consecutive euthyroid patients with scintigraphically proven goitre, and compared to 26 control subjects. E.T. was quantified using the 81mKr transit time, a highly sensitive technique capable of detecting even minor E.T. disorders. Abnormal E.T. was observed in 39% of goitrous patients, while it was normal in all controls. Occurrence of delayed E.T. was not correlated with either goitre firmness, the presence of symptoms of neck discomfort, difficulties in swallowing, or nodularity. E.T. delay was more frequent and more severe with larger goitres. In addition, E.T. delay was significantly correlated with asymmetry and "low lying" goitres. In summary, the present studies are the first demonstration of frequent E.T. anomalies in goitrous patients. The data suggest that E.T. impairment could be mediated by two mechanisms: a direct compression effect in patients with large, asymmetrical, partially retrosternal goitres; and an indirect functional esophageal anomaly in patients with small goitres.

Adolescent↗
PubMed1987

Comparison of two 99mTc(V)-dimercaptosuccinic acid preparations.

99mTc(V)-DMSA labelled either by increasing the pH together with a low concentration of Sn, or by increasing the pH only are compared in vitro and in vivo. The gel chromatographic separation shows that after incubation with blood, all the 99mTc(V)-DMSA preparations are stable and do not bind to the plasma proteins. The behavior in rats as well as in clinical studies does not demonstrate any distinctive characteristics between the different radiomolecules. It seems that the pH of the solution is an important factor which controls the formation of 99mTc(V)-DMSA.

Animals↗