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Biomedical subjects

M J Klein

Publications and source records attributed to M J Klein.

At least 19 recordsLinked to original sources
PubMed1992

Case report 754: Xanthoma of the Achilles tendon.

The MRI features of bilateral xanthoma of the achilles tendon in type II hyperlipoproteinemia are reported. MRI has proved to be the best imaging modality available in assessing enlargement of the Achilles tendon. It demonstrates the heterogeneous signal on both T1- and T2-weighted images where the xanthomatous deposits are relatively higher in signal intensity than the tendon itself. MRI also has a potential value in the clinical assessment and therapeutic response of the xanthoma after operative intervention.

Achilles Tendon↗
PubMed1992

Case report 711: Parosteal osteosarcoma of left femur.

We present a patient with parosteal osteosarcoma. The lesion arose at the surface of the femur without involvement of the marrow cavity. Some 24 months following resection of the involved bone, she developed distant metastases with no evidence of local recurrence. Neither the primary nor the metastatic lesions showed high-grade malignancy.

Adult↗
PubMed1992

Differentiation of the melanotrophic cells of rat pituitary primordium in organotypic culture in defined medium.

Organotypic cultures, in defined medium, of pituitary primordia obtained from 15-day-old rat fetuses were performed in order to study the in vitro differentiation of melanotrophic cells. The morphological and ultrastructural features of the transplants resembled those of the gland developing in vivo. In situ hybridization on semi-thin sections, using a 35S-labelled oligonucleotide probe, revealed pro-opiomelanocortin-mRNA-containing cells on the first day of culture in the anterior lobe and after 2-3 days in the intermediate lobe. Immunoperoxidase labelling of adjacent sections showed that the same cells reacted with antibodies against alpha-melanocyte-stimulating hormone (alpha MSH), gamma 3MSH and adrenocorticotropic hormone in both lobes. The pro-opiomelanocortin-mRNA-containing cells formed progressively conspicuous areas in the intermediate lobe, which was almost uniformly labelled after 6 days. In the anterior lobe, these cells remained scattered in small cell groups, and colloidal gold immunolabelling showed the progressive disappearance of alpha MSH labelling from the secretory vesicles in cells exhibiting morphological features of adult corticotrophic cells. Both the alpha MSH content of the explants and alpha MSH release into the culture medium increased with time. Treatment with the dopamine agonist bromocriptine induced a strong dose-dependent decrease in alpha MSH secretion, which was significant after 3 days in culture, indicating that dopamine D2 receptors are able to regulate hormonal release of melanotrophic cells at early stages. This system constitutes a suitable model for further studies of factors controlling cell differentiation and cellular interactions involved in histogenesis.

Adrenocorticotropic Hormone↗
PubMed1992

Case report: angiosarcoma occurring in a bone infarct.

An unusual case of an angiosarcoma that occurred in a bone infarct is presented. A bone infarct may occasionally dedifferentiate to an osteogenic sarcoma or a malignant fibrous histocytoma. However, the association of angiosarcoma with a bone infarct is extremely rare. To the best of our knowledge, there is only one other report of this association in the English literature.

Bone Neoplasms↗
PubMed1992

Tumour and tumour-like conditions of the soft tissue: magnetic resonance imaging features differentiating benign from malignant masses.

49 primary soft-tissue masses were studied by magnetic resonance imaging (MRI) in an effort to differentiate benign from malignant lesions. There were 24 benign and 25 malignant tumours. Images were evaluated for the presence of low-signal septation, changes in pattern of homogeneity, signal intensity, and margin definition and shape. 20 of the 25 malignant tumours (80%) demonstrated low-signal septation, and two of the 24 benign tumours (8%) also demonstrated this feature. Malignant tumours tended to change pattern from being homogeneous on T1-weighted images to being heterogeneous on T2-weighted images (72%). Benign tumours maintained their pattern on both sequences (67%). Only three of the 24 benign tumours (12.5%) changed from being homogeneous to heterogeneous. Our findings suggest that tumours which change pattern, from homogeneous on T1-weighted images to heterogeneous on T2-weighted images, and tumours which have low-signal septations are likely to be malignant. Moreover benign lesions tend to have well defined margins, and some benign masses have characteristic appearances that aid in their differentiation from malignant processes.

Adolescent↗
PubMed1992

Intramuscular myxoma: magnetic resonance features.

Magnetic resonance imaging (MRI) was performed in six cases of intramuscular myxoma of the extremities and revealed the following characteristics. All tumours were confined to muscle and had a sharply defined border. All had a signal intensity lower than skeletal muscles on T1-weighted images and brighter than fat on T2-weighted images. The signals were homogeneous on both T1- and T2-weighted images. This study did not include contrast enhancement. The diagnosis was confirmed by an open biopsy. All tumours were resected with no recurrence. Diagnosis based on these MRI characteristics was incorrect in two cases of intramuscular ganglia and in a case of intramuscular cysticercus cellulose. MRI features of intramuscular myxoma are typical in the majority of cases. Benign intramuscular lesions that contain mainly fluid can mimic intramuscular myxomas.

Adult↗
PubMed1992

Leukocyte scanning with 111In is superior to magnetic resonance imaging in diagnosis of clinically unsuspected osteomyelitis in diabetic foot ulcers.

OBJECTIVE: To compare the accuracies of MRI and leukocyte scanning in diagnosing clinically unsuspected osteomyelitis in diabetic foot ulcers. RESEARCH DESIGN AND METHODS: A prospective study of 16 diabetic foot ulcers in 12 patients, including both ambulatory and hospitalized patients, was performed at a university medical center. Pedal images were obtained by leukocyte scanning with [111In]oxyquinoline and MRI. Definitive diagnosis of osteomyelitis then was determined by bone biopsy for culture and histology. RESULTS: Biopsy-proven osteomyelitis was present in 7 (44%) of the 16 foot ulcers. The diagnosis was suspected clinically in 0%. Leukocyte scanning was 100% sensitive, whereas MRI was only 29% sensitive in diagnosing osteomyelitis in diabetic foot ulcers. Specificities were 67 and 78%, respectively. The positive and negative predictive values (70 and 100%, respectively) for the leukocyte scan also were greater than those of MRI (50 and 58%, respectively). CONCLUSIONS: Leukocyte scanning is superior to MRI in detecting clinically unsuspected osteomyelitis in diabetic foot ulcers.

Biopsy↗
PubMed1992

Hemangiomas of the long tubular bone.

The overall spectrum of hemangiomas involving long tubular bones is exemplified by three cases, the first being medullary, the second periosteal, and the third intracortical. The clinical presentation was progressive pain at the site of the lesion in all cases. The medullary hemangioma involved the distal shaft of the humerus and was entirely radiolucent. The periosteal tumor was exceptional in that it affected the proximal shaft of the tibia in contrast to the seven previously reported cases that involved the midshaft of the bone. The intracortical hemangioma was in the tibia, the site of all three previously reported cases. Hemangioma of bone may show variable roentgenographic patterns related to the anatomic location and the type of involved bone. The final diagnosis is dependent on histologic evaluation.

Adult↗
PubMed1991

Unsuspected osteomyelitis in diabetic foot ulcers. Diagnosis and monitoring by leukocyte scanning with indium in 111 oxyquinoline.

OBJECTIVE: The prevalence of osteomyelitis in diabetic foot ulcers is unknown. Early diagnosis of this infection is critical, as prompt antibiotic treatment decreases the rate of amputation. We therefore assessed the prevalence of osteomyelitis in 35 diabetic patients with 41 foot ulcers. We compared results of roentgenograms, leukocyte scans with indium In 111 oxyquinoline, and bone scans with the diagnostic criterion standards of bone histologic and culture findings. Leukocyte scans were repeated at 2- to 3-week intervals during antibiotic treatment. DESIGN: Cohort study. SETTING: Institutional and private, ambulatory and hospitalized patients. PATIENTS: Consecutive sample of 54 diabetic patients. Thirty-five patients with 41 foot ulcers were included. RESULTS: As determined by bone biopsy and culture, osteomyelitis was found to underlie 28 (68%) of 41 diabetic foot ulcers. Only nine (32%) of the 28 cases were diagnosed clinically by the referring physician. Underscoring the clinically silent nature of osteomyelitis in these ulcers, 19 (68%) of 28 occurred in outpatients, 19 (68%) of 28 occurred in ulcers not exposing bone, and 18 (64%) of 28 had no evidence of inflammation on physical examination. All patients with ulcers that exposed bone had osteomyelitis. Of the imaging tests, the leukocyte scan had the highest sensitivity, 89%. In patients with osteomyelitis, the leukocyte scan image intensity decreased by 16 to 34 days of antibiotic treatment and normalized by 36 to 54 days. CONCLUSION: The majority of diabetic foot ulcers have an underlying osteomyelitis that is clinically unsuspected. Leukocyte scans are highly sensitive for diagnosing osteomyelitis in diabetic foot ulcers and may be useful for monitoring the efficacy of antibiotic treatment. We recommend that diabetic patients with foot ulcers that expose bone should be treated for osteomyelitis. Diabetic patients with foot ulcers that do not expose bone should undergo leukocyte scanning, which eliminates the risk of bone biopsy in diagnosing osteomyelitis and allows for the diagnosis and treatment of this well-known but often silent precursor of lower extremity amputation.

Diabetes Mellitus, Type 2↗
PubMed1991

Fibromyxoma of bone.

We report two cases of fibromyxoma, one affecting the iliac crest and the second involving the proximal shaft of the tibia. Fibromyxoma is a rare neoplasm related to benign fibrous tumors and is characterized by exuberant, extracellular, ground substance production. Its histologic appearance is benign and distinctive and can be readily distinguished from that of myxoid chondrosarcoma or chondromyxoid fibroma. The radiographic picture is, however, difficult to interpret, and the entity can be easily mistaken for other tumors.

Adult↗
PubMed1991

Skeletal manifestations of granulocytic sarcoma (chloroma).

Skeletal manifestations of chloroma were reviewed in five patients. In four cases, a chloroma was the initial manifestation of a systemic disease. In the fifth, an elderly patient developed a bone lesion during a blastic crisis while under treatment for chronic myelogenous leukemia. Two patients presented with lytic lesions of the ribs, two with lytic lesions of the femur, and one with a predominantly sclerotic lesion of the scapula. The laboratory findings in two patients were within normal limits. All lesions were confirmed by bone biopsy.

Adult↗
PubMed1991

Case report 696: Chondroblastoma of the right acetabulum and superior pubic ramus.

A case of chondroblastoma involving the right acetabulum and superior pubic ramus in a 60-year-old man has been presented. Tissue was obtained by open biopsy. The clinical and radiographic characteristics of chondroblastoma in general, and this tumor in particular, were discussed. The histopathology and differential diagnosis were also considered. The relatively uncommon site of the tumor and its occurrence in an older patient made the radiographic diagnosis difficult, and other possibilities were discussed.

Acetabulum↗
PubMed1991

Systematic presence of GABA-immunoreactivity in the tubero-infundibular and tubero-hypophyseal dopaminergic axonal systems: an ultrastructural immunogold study on several mammals.

Immunoreactivities for tyrosine hydroxylase (TH), gamma-aminobutyric acid (GABA) and, in some cases, glutamic acid decarboxylase (GAD) were detected by light and electron microscopy in axons projecting into the median eminence and pituitary gland of various mammals (rats, mice, guinea pigs, cats, rabbits and hares). Light microscope immunoperoxidase reactions were performed on adjacent semithin sections of plastic-embedded samples. In the median eminence external zone, the distributions of the TH- and GAD- or GABA-immunoreactive endings were very similar in the anterior and lateral areas, while medially the GABA-labelled endings predominated. Comparable distribution patterns were found in the various species examined. In the pituitary gland, the distributions of GABA- and TH-immunoreactivities were superimposable in the intermediate lobes of all species examined, except in the rabbit and hare in which both types of innervation were lacking. For electron microscopy, the immunogold procedure was applied to sections of lowicryl-embedded samples; simultaneous detection of GABA- and TH-immunoreactivities was enabled by recto-verso double labelling with gold particles of distinct diameters. In the median eminence, GABA-immunoreactivity occurred systematically in the TH-positive endings, while distinct GABA-positive/TH-negative axons were also detected. In the intermediate lobe, the colocalization of TH- and GABA-immunoreactivities was a constant feature of the axons innervating the melanotrophic cells in all the species examined, except in the Leporidae. The functional significance of this colocalization remains to be determined.

Animals↗
PubMed1991

RU 41,656 does not reverse the scopolamine-induced cognitive deficit in healthy volunteers.

The potential antagonism of a single oral dose of RU 41,656 10 mg on the memory and attention disturbances induced by scopolamine 0.6 mg s.c. have been investigated in a 3 period, placebo controlled, double blind, cross over study in 12 healthy, young volunteers. The effects of the compounds were evaluated by objective tests (Buschke selective reminding test, CFF, simple reaction time, tapping, arithmetical calculation) and subjective measurements (visual analogue scale, side effects questionnaire). Measurements were taken before treatment and 2, 4 and 7 h after RU 41,656. Scopolamine caused anterograde amnesia and sedative effects as which were not counteracted by RU 41,656.

Adult↗
PubMed1991

Study of the potential reversal of triazolam memory and cognitive deficits by RU 41 656 in healthy subjects.

The potential antagonism of a single oral dose of RU 41 656 (10 mg) on the memory and attention disturbances induced by oral administration of triazolam (0.25 mg) have been investigated in a 3-period, placebo controlled, double blind, cross-over study involving 12 healthy young volunteers. The effects of the compounds were evaluated by objective tests (Buschke selective reminding test, CFF, simple reaction time, tapping, arithmetical calculation) and subjective measurements (visual analogue scale, side effects questionnaire). Measurements were taken before treatment and 2, 4 and 7 h after RU 41 656 intake. Triazolam caused anterograde amnesia as already described with other benzodiazepine with few sedative effects at this dosage. Under the experimental conditions of the trial, RU 41 656 failed to counteract the memory deficits induced by triazolam.

Adult↗
PubMed1991

Transarticular invasion of joints by bone tumors: hypothesis.

Eight bone tumors with associated transarticular invasion of the sacroiliac joints are described. All invaded the true synovial joint and spread to the opposing bone. One tumor was benign, and the other seven were malignant. Five of the seven were primary and two were metastatic cancer. One, a myeloma, invaded the disc spaces between the fourth and fifth lumbar vertebrae and the fifth lumbar vertebra and sacrum as well as the sacroiliac joint. The right facet joints of the two vertebrae were also invaded. After a thorough search of the literature, we find that the sacroiliac joint is the most common joint to be invaded by tumors. This is followed by the vertebral disc spaces and, last, the facet joints. Apart from these joints, we were unable to find any radiographic documentation of other joints being transarticularly invaded by tumors. We noted that there is a direct relation between transarticular tumor spread and joints that lack mobility and that certain tumors, benign and malignant, tend to invade these joints.

Adult↗
PubMed1991

Epiphyseal involvement in osteosarcoma.

Plain radiography and magnetic resonance (MR) imaging were used to assess the extent of transphyseal involvement in 15 consecutive patients with long bone osteosarcoma and nonfused epiphyses. The findings were correlated with those from surgical and microscopic pathologic examinations. There were no cases of false-positive findings with either MR imaging or plain radiography. Conventional radiography accurately helped predict transphyseal spread in only nine of 15 cases (60%). Spread to the epiphysis was present in 12 of the 15 cases (80%) and was accurately predicted with MR imaging in all 12 cases. This finding contradicts the common misconception that the physis acts as a "barrier" to tumor spread.

Adolescent↗