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Biomedical subjects

H K Genant

Publications and source records attributed to H K Genant.

At least 415 records · Page 23Linked to original sources
PubMed1983

Hereditary chondrocalcinosis in a Mexican-American family.

In a study of 45 adults in a family of Mexican-Indian ancestry, it was found that 22 (49%) had joint symptoms resembling those of degenerative joint disease. Eleven family members had radiographic evidence of chondrocalcinosis, and 1 adult and 3 adolescents had clinical histories and examinations consistent with the familial arthropathy, but no radiographic evidence of disease. The cause of the arthritis in the affected family members is calcium pyrophosphate crystal deposition. The mode of inheritance appears to be autosomal dominant with a high degree of penetrance. The disease is characterized by onset in the second to fifth decades of either episodes of acute inflammatory arthritis or degenerative joint disease. A unique finding of this study was a "halo" surrounding chondrocytes in 1 patient's cartilage, demonstrating loss of the proteoglycans.

Adult↗
PubMed1983

Chronic repetitive trauma: a cause of atypical degenerative joint disease.

Six cases of amateur athletes who have severe atypical degenerative joint disease (DJD) are presented; their histories suggest that chronic, repetitive trauma was causative in the development of their arthropathy. Although many examples of this process have been reported in professional athletes, it has not been reported in amateurs. As participation in athletic activities increases we can, perhaps, expect to see more of this type of DJD in the future.

Adult↗
PubMed1983

Clinical nuclear magnetic resonance imaging of the body.

NMR promises great advances in diagnosis and has delivered so much already that it is expected that in the future it will replace many applications of the currently used imaging modalities. Although x-ray computed tomography is continuing to advance in speed of scanning and resolving power, NMR will most likely soon eliminate its use in many studies of the central nervous system and also in many other areas of the body. The promise of combining topical spectroscopy with imaging is also exciting and should provide further information about metabolic processes of various organs. Progress in NMR is so rapid and the future is so bright that one of the great problems will be to develop a new breed of radiologists who are versatile in biochemistry, mathematics, and computers, as well as competent in morphologic anatomy and pathologic physiology. As time goes on, advances in NMR will be achieved only by teams of clinical and basic scientists encompassing multiple disciplines.

Aortic Aneurysm↗
PubMed1983

Musculoskeletal applications of nuclear magnetic resonance.

Thirty healthy subjects and 15 patients with a variety of musculoskeletal disorders were examined by conventional radiography, computed tomography (CT), and nuclear magnetic resonance (NMR). NMR proved capable of demonstrating important anatomic structures in the region of the lumbosacral spine. Lumbar disk protrusion was demonstrated in three patients with CT evidence of the disease. NMR appeared to differentiate annulus fibrosus from nucleus pulposus in intervertebral disk material. Avascular necrosis of the femoral head was demonstrated in two patients. The cruciate ligaments of the knee were well defined by NMR. Muscles, tendons and ligaments, and blood vessels could be reliably differentiated, and the excellent soft-tissue contrast of NMR proved useful in the evaluation of bony and soft-tissue tumors. NMR holds promise in the evaluation of musculoskeletal disorders.

Adolescent↗
PubMed1983

Recognition of lumbar disk herniation with NMR.

Fifteen nuclear magnetic resonance (NMR) studies of 14 patients with herniated lumbar intervertebral disks were performed on the UCSF NMR imager. Computed tomographic (CT) scans done on a GE CT/T 8800 or comparable scanner were available at the time of NMR scan interpretation. Of the 16 posterior disk ruptures seen at CT, 12 were recognized on NMR. Diminished nucleus pulposus signal intensity was present in all ruptured disks. In one patient, NMR scans before and after chymopapain injection showed retraction of the protruding part of the disk and loss of signal intensity after chemonucleolysis. Postoperative fibrosis demonstrated by CT in one patient and at surgery in another showed intermediate to high signal intensity on NMR, easily distinguishing it from nearby thecal sac and disk. While CT remains the method of choice for evaluation of the patient with suspected lumbar disk rupture, the results of this study suggest that NMR may play a role in evaluating this common clinical problem.

Adult↗
PubMed1983

Advances in CT assessment of metabolic and endocrine disorders.

Advances in diagnostic imaging of endocrine disorders are occurring rapidly. In certain disease entities, such as Cushing's disease, pheochromocytoma, primary aldosteronism, and islet cell tumors, noninvasive imaging techniques like CT have become the initial diagnostic imaging procedures of choice. In other disorders, such as hyperparathyroidism, carcinoid, and thyroid disease, CT is making important contributions, and further advances can be anticipated.

Adrenal Gland Diseases↗
PubMed1982

Incidence of radiographically evident bone disease, nephrocalcinosis, and nephrolithiasis in various types of renal tubular acidosis.

The syndrome of renal tubular acidosis has been categorized into three physiologic types that have different clinical findings and prognostic and therapeutic implications. We reviewed radiographs of the skeleton and kidneys in 92 patients (56 children and 36 adults) with renal tubular acidosis in order to determine whether the radiologic findings could be related to the type of syndrome. Forty-four patients had Type 1 renal tubular acidosis, 18 had Type 2, and 30 had Type 4. Evidence of skeletal abnormalities was uncommon (17 per cent) and was confined to patients who had the Type 2 disorder or azotemia. The children with Type 2 and skeletal abnormalities had rickets; the adults had osteopenia without pseudofractures. Nephrocalcinosis was evident in approximately one fourth of the group (29 per cent) and was restricted to patients with the Type 1 syndrome. In patients with Type 4, osteopenia was evident in 12 per cent, all of whom were azotemic. Our observations indicate that the radiographic manifestations of renal tubular acidosis are influenced by the physiologic type of renal tubular acidosis.

Acidosis, Renal Tubular↗
PubMed1982

Quantitative computed tomography of vertebral spongiosa: a sensitive method for detecting early bone loss after oophorectomy.

We assessed serially the bone mineral loss in 37 premenopausal women for 24 months after oophorectomy and determined the dose-response for conjugated estrogen therapy in preventing this loss. Spinal cancellous bone was measured by quantitative computed tomography and measurement of appendicular cortical bone by radial photon absorptiometry and metacarpal radiogrammetry. For the placebo and low-dose treatment groups, the mean annual bone mineral losses were 7% to 9% from the vertebral spongiosum and 1% to 3% from the peripheral cortex. The correlation between axial and appendicular loss was weak (r = 0.581), precluding a reliable estimate of spinal loss from peripheral measurements. For the maximal-dose group (0.6 mg/d), the mean annual bone mineral losses were less than 0.5% from the axial and appendicular sites, and were not significant. The results indicate that spinal quantitative computed tomography provides a highly sensitive measurement of bone mineral loss after oophorectomy, that bone mineral loss is five- to sevenfold greater from the spinal spongiosum than from the appendicular cortex, and that conjugated estrogen in doses of less than 0.6 mg/d are inadequate to prevent the vertebral mineral loss.

Adult↗
PubMed1981

Pseudohypoparathyroidism presenting as renal osteodystrophy.

Pseudohypoparathyroidism (pseudo HPT) is the prototype of a group of diseases with end organ unresponsiveness to parathyroid hormone (PTH). Patients with the classic form of this disease have both renal and osseous resistance to PTH. We describe a rare variant of pseudo HPT with classic renal unresponsiveness to PTH but normal skeletal responsiveness to this hormone. The latter patients develop metabolic bone disease in response to depressed calcium and elevated PTH levels. Skeletal abnormalities are histologically and radiologically indistinguishable from renal osteodystrophy and these patients frequently present in childhood with symptoms relating to slipped capital femoral epiphyses. The latter radiologic findings, in the face of normal renal function or the classic somatic features of the syndrome, are highly suggestive of pseudo HPT with normal skeletal responsiveness to PTH.

Calcium↗
PubMed1981

Quantitative and qualitative comparison of two microfocus-tube imaging systems.

Two microfocus-tube magnification systems were compared: one used an RSI tube (stationary anode, Pierce-gun cathode) and the other used a GE tube (rotating anode, biased cathode). Imaging parameters for body parts of three thicknesses, the hand (low), knee (medium), and hip (high), were considered at a magnification of 2. The focal-spot MTF was measured on and off the central ray of the beam, as well as beam quality and the intensity of scatter in the image plane. Patient exposures were also determined. While both systems gave high-quality images at acceptable exposure levels, the RSI unit was judged superior for body parts up to 15 cm thick. For thicker parts, scatter degraded contrast with the RSI unit, making the GE unit superior.

Humans↗