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Biomedical subjects

R H Michael

Publications and source records attributed to R H Michael.

14 recordsLinked to original sources
PubMed1999

Serum concentrations of steroids, parathyroid hormone, and calcitonin in postmenopausal women during the year following hip fracture: effect of location of fracture and age.

BACKGROUND: Hip fracture in the aged is a major health problem, especially considering the increasing proportion of the elderly in the population. This study examines changes in circulating levels of hormones, which are purported to affect bone metabolism, in response to hip fracture in postmenopausal women. METHODS: Patients consisted of women ages 65 and older who had surgery within 2 days of fracture. Serum samples were obtained at 3, 10, 60, 180, and 360 days postfracture. Healthy women without hip fractures from the same age range served as a control group (n = 17). Hormones were determined by radioimmunoassay. Subjects with fractures in the neck region of the femur (n = 78) were compared to subjects with fractures in the trochanteric region (n = 88). RESULTS: Estrone concentration (47.6 +/- 5.7 pg/mL; mean +/- SEM) at 3 days postfracture was elevated (p < .001) compared to control levels of 20.7 +/- 4.6 pg/mL. By 2 months, levels had declined to control levels. Androstenedione and the adrenal hormones, DHEAS and cortisol, displayed similar responses. Parathyroid hormone (PTH) levels were not significantly different from the control concentration at 3 days following fracture, but increased (p < .001) during the year following fracture. Calcitonin concentrations were much higher (p < .001) 3 days postfracture (42.1 +/- 3.7 pg/mL) compared to controls without fracture (9.8 +/- 3 pg/mL). Except for testosterone, no differences could be attributed to fracture location. Only PTH, with concentrations higher in the older age groups (p < .001), showed an age-related response. CONCLUSIONS: Following hip fracture, there are some dramatic responses in hormones that purportedly are mechanistically important in bone metabolism. These changes include transient increases in steroid hormones, chronic elevations in calcitonin, and rising levels of PTH during the year after fracture.

Aged↗
PubMed1994

A skin suture for foot and ankle surgery.

Severe swelling and skin necrosis are not uncommon following foot and ankle surgery, particularly trauma surgeries. A skin suture technique is presented that has the advantages of being simple, providing good skin eversion and apposition with minimal tension and risk of ischemia, and being easy to remove. The suture technique has been used by the authors for the past 2 years on all foot and ankle trauma and reconstructive cases in which severe swelling was anticipated. There have been no instances of skin necrosis, significant epidermolysis, or dehiscence, and the appearance of the scar is acceptable.

Aged↗
PubMed1992

Isolation and purification of calmodulin from the shrimp, Crangon crangon.

Calmodulin was isolated and purified from shrimp abdominal muscle by heat precipitation, ion exchange and hydrophobic interaction chromatography. The purified calmodulin was homogeneous when evaluated by polyacrylamide gel electrophoresis. A still remaining contaminant was eliminated by high performance liquid chromatography on a phenyl column. The biological and physicochemical properties of shrimp calmodulin such as amino acid composition, molecular weight and the ability to activate calmodulin-deficient bovine heart phosphodiesterase were compared to those of other invertebrate calmodulins.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1991

Chronic compartment syndrome caused by aberrant fascia in an aerobic walker.

The following is a case presentation of a 36-yr-old female athlete who presented with the symptoms and signs of chronic anterior compartment syndrome. Pre-exercise and post-exercise tissue pressure measurements revealed increased compartment pressures in both of her anterior leg compartments. Aberrant fascial bands overlying and compressing the anterior compartments were discovered at the time of surgery. Fasciotomies led to complete recovery and return to previous levels of athletic activity. This is the first report of aberrant fascia as a cause of chronic anterior compartment syndrome.

Adult↗
PubMed1990

Radionuclide bone imaging in the early detection of fractures of the proximal femur (hip): multifactorial analysis.

The results of 179 radionuclide bone imaging examinations, 105 gathered retrospectively from the cases of 97 patients referred for assessment of possible occult fracture of the proximal femur (hip) and 74 performed prospectively on 63 patients referred with a diagnosis of obvious or suspected hip fracture, were analyzed in relation to patient age, the interval between injury and imaging, and the type of fracture sustained. Ninety-two examinations were performed less than 72 hours after injury; 31 of these were done at 0-24 hours. For the diagnosis of hip fracture in an individual patient, the overall sensitivity was 0.933; specificity, 0.950; positive predictive value, 0.918; and negative predictive value, 0.960. For the clinically important subgroup of 145 patients with normal or equivocal radiographs, the sensitivity was 0.978. A characteristic pattern for greater trochanter fractures was found. Other diagnoses were scintigraphically established in 41% of patients evaluated. The data suggest that patients of all ages, regardless of the time after injury, can be imaged as soon as they present.

Adult↗
PubMed1985

Anterior portal selection for shoulder arthroscopy.

A posterior portal site has become the accepted standard for introduction of the arthroscope for routine diagnostic procedures of the shoulder. Few published guidelines exist, however, on the optimum and safe positions of accessory portals for introduction of a probe or surgical instruments during shoulder arthroscopy. The relatively thick surrounding muscle layers and the close proximity of vital neurovascular structures would make guidelines for safer and more reproducible accessory portal selection helpful to minimize the risk of injury to these structures. The "intraarticular triangle" bounded by the humeral head, the glenoid rim, and the biceps tendon has been found to be an excellent intraarticular landmark for placement of an accessory anterior portal for shoulder arthroscopy. Anatomical dissections on 20 cadaver shoulders have confirmed that instruments passed through this location are at little risk to injure adjacent neurovascular structures about the shoulder. Clinical data in 30 shoulder arthroscopies performed utilizing this landmark for placement of an anterior portal have confirmed this position to be a safe and useful location for portal placement if proper precautions are followed.

Arthroscopy↗
PubMed1984

The specific scintigraphic pattern of "shin splints in the lower leg": concise communication.

The clinical entity, "shin splints," is now being recognized, and more specifically characterized by the findings of exercise-induced pain and tenderness to palpation along the posterior medial border of the tibia. In this prospective study, ten patients with this syndrome were evaluated using three-phase bone scintigrams, and a specific scintigraphic pattern was determined. Radionuclide angiograms and blood-pool images were all normal. On delayed images, tibial lesions involved the posterior cortex, were longitudinally oriented, were long, involving one third of the length of the bone, and often showed varying tracer uptake along that length. Obtaining both lateral and medial views was crucial. The location of activity suggested that this entity is related to the soleus muscle. These scintigraphic findings can be used to differentiate shin splints from stress fractures or other conditions causing pain in the lower leg in athletes.

Adolescent↗
PubMedDate not supplied

The soleus syndrome. A cause of medial tibial stress (shin splints).

Radionuclide bone scans have demonstrated linear uptake along the posterior medial border of the tibia in patients with shin splints. This area was investigated by anatomical dissection (14 human cadavers), electromyographic (EMG) and muscle stimulation studies (10 patients), and open biopsy (1 patient). Histologically, the increased metabolic activity manifested on the radionuclide scan is due to a periostitis with new bone formation. The soleus muscle and its investing fascia are anatomically and biomechanically implicated in the production of these stress changes, particularly when the heel is in the pronated position. The soleus muscle and fascia form a tough "soleus bridge" over the deep compartment which is thought to be important in patients requiring surgical decompression.

Adolescent↗
PubMedDate not supplied

Morphologic and histologic abnormalities in female and male rats treated with anabolic steroids.

A two-part study was performed to determine the effects of high doses of anabolic steroids on weight, appetite, and organ histology. Initially, 30 white Wistar rats, 15 males and 15 females, were treated weekly with either 0.52 cc of physiologic saline or nandrolone decanoate. After 6 weeks, female treated and control rats had comparable weight gains, but male treated rats were significantly lighter than controls. Rats were sacrificed and organs dissected for histologic preparation. Treated male livers had less lipid than control males. The uteri of treated females displayed abnormal vacuolization, stromal edema, and peliosis. In Part II, 12 male rats, 6 treated and 6 control, were given the drug or saline in a manner identical to that in Part I. Treated rats had lower weights from Weeks 1 through 6 and ate less than controls. Upon sacrifice, treated rats' kidneys were heavier, and testes and liver were lighter compared to controls. Roentgenographic studies of tibias from Parts I and II showed no significant differences in tibial length or height of growth plate between treated and control groups. In summary, when anabolic steroid use is studied in the rat model, numerous pathological and anatomical changes occur.

Anabolic Agents↗
PubMedDate not supplied

Malignant fibrous histiocytoma associated with bone infarcts: report of a case.

A caisson worker with symmetrical bone infarcts in the tibiae demonstrated a malignant transformation of one of the bone infarcts with wide-spread metastases to the lungs and viscera. Histologically, the tumor was found to be a malignant fibrous histiocytoma and despite amputation, the patient died approximately one year following the diagnosis. This case lends credence to the concept of a cause and effect relationship existing between bone infarcts and the subsequent development of bone sarcoma.

Adult↗
PubMedDate not supplied

Pigmented villonodular synovitis.

Pigmented villonodular synovitis, a rare tumor of the synovial lining of a joint, is suggested when aspiration of a chronically swollen and painful single joint (usually the knee) yields a brownish fluid. The diagnosis is confirmed by biopsy, and the preferred treatment is complete excision of all involved synovial tissue. The recurrence rate is directly related to the degree of synovial involvement and to the thoroughness of the synovectomy performed. Although pigmented villonodular synovitis does not become malignant, it can destroy a joint so that an arthroplastic procedure may be necessary.

Arthroscopy↗