Biomedical subjects

M Terk

Publications and source records attributed to M Terk.

9 recordsLinked to original sources

PubMed2001

The effects of eccentric velocity on activation of elbow flexors: evaluation by magnetic resonance imaging.

PURPOSE: To compare magnetic resonance imaging (MRI) signal intensity changes in the primary elbow flexors during two isotonic exercise protocols varying in eccentric velocity and the ratio of eccentric to concentric activity. METHODS: Twelve men performed two exercise protocols. The right and left arms were randomly assigned to one of two protocols that had the same workload (60% 1RM) and same total time of exercise (144 s) but differed in the velocity and ratio of eccentric to concentric activity (1:1 and 5:1 for the fast and slow protocols, respectively). MRI signal intensity changes were quantified pre- and post-exercises using an inversion recovery sequence with a 1.5T MRI system (TR = 2500 ms, TE = 90 ms, TI = 140 ms). Percent change in MRI signal intensity, rate of perceived exertion (RPE), and delayed onset muscle soreness (DOMS) were recorded and analyzed. RESULTS: The biceps brachii was found to be preferentially recruited during the fast protocol compared with the brachialis, whereas the brachialis was found to be preferentially recruited during the slow protocol (P < 0.05). The fast exercise protocol was perceived as being more strenuous (RPE = 8.3 +/- 2.1) than the slow (RPE = 5.4 +/- 1.5, P < 0.05) and produced DOMS in 58% of the tested subjects. CONCLUSIONS: These results suggest that agonists respond to various loading conditions nonhomogeneously. These findings may have implications with respect to exercise prescriptions for specific muscles.

Adult↗

PubMed1999

MRI evaluation of post-operative seromas in extremity soft tissue sarcomas.

OBJECTIVE: To define the spectrum of MRI appearances of postoperative seromas in patients who have undergone excision of extremity soft tissue sarcomas. Local recurrence is always of concern; often a second-look procedure is performed to assess this possibility. Unnecessary surgical exploration may be avoided if radiologists and orthopedic oncologists are familiar with this spectrum of MRI appearances. DESIGN AND PATIENTS: The medical records and images of 85 patients with extremity soft tissue sarcomas were reviewed. Postoperative MRI examinations were available in 46 patients. Eight of these demonstrated MRI evidence of postoperative seroma. The initial size, rate of change, margin, and internal architecture of each seroma was measured, calculated, graded, and graphed. RESULTS AND CONCLUSION: MRI is an excellent modality for the evaluation of postoperative seromas. Globular areas of low to intermediate signal material within seromas may represent organized hematomas or granulation tissue rather than sarcoma recurrence. Local recurrence rarely occurs within seromas.

Adult↗

PubMed1997

A new technique for performing Syed-Neblett template interstitial implants for gynecologic malignancies using transrectal-ultrasound guidance.

PURPOSE: Interstitial brachytherapy plays an important role in the treatment of advanced and recurrent gynecologic malignancies. Unfortunately, the inability to visualize the tumor and surrounding normal structures during the implant has hampered the accuracy and safety of the implant. Transrectal ultrasound guided Syed-Neblett template implantation is a new technique for performing interstitial implants under direct visualization. The details of the technique are presented to demonstrate the ability to accurately guide needle placement into tumor and avoid needle insertion into critical surrounding normal structures. METHODS AND MATERIALS: The transrectal ultrasound is positioned so that it can visualize the tumor, and normal surrounding structures in both transverse and longitudinal planes. The Syed-Neblett template is positioned and sutured into the perineum. Needles are inserted into the target area under direct visualization through transverse imaging. The bladder and rectum can be directly imaged and thus avoided. Longitudinal imaging is then used to guide the needles to the appropriate depth. In addition, it can be used to assess the length of the target volume and aid in determining the active length of the sources. RESULTS: A total of 12 procedures have been performed on seven patients from August 30, 1995 to April 12, 1996. The presenting diseases included: Stage IIIb cervical cancer in four cases, recurrent endometrial cancer in two cases, and Stage III vaginal cancer in one case. The total length of time for implantation of the needles ranged from 45 to 165 min (median--130 min). CONCLUSION: Transrectal ultrasound guidance provides real-time visualization of the target volume and normal tissues during interstitial implantation of gynecologic malignancies and allows for accurate needle placement.

Aged↗

PubMed1997

Enhanced radiosensitization with interferon-alpha-2b and cisplatin in the treatment of locally advanced cervical carcinoma.

PURPOSE: To evaluate the efficacy and toxicity of interferon-alpha-2b (IFN-alpha) and cisplatin given concomitantly with radiation therapy (RT) in the treatment of locally advanced cervical carcinoma. MATERIALS AND METHODS: Twenty-one patients with stage bulky Ib-IIIb (Ib, 2; IIa, 2; IIb, 8; IIIb, 9) cervical carcinoma were treated with combined IFN-alpha (5 million IU) subcutaneously three times per week and cisplatin (25 mg/m2) i.v. infusion over 2 h weekly for 7 weeks, given concomitantly with RT (4500 cGy of external beam plus 2 brachytherapy procedures). Total radiation doses delivered ranged from 7500 to 9960 cGy (median, 9300 cGy). Follow-up ranged from 16 to 33 months (median, 25 months). RESULTS: The 2-year local control rate was 100%. The only sites of disease recurrence were distant. Freedom from distant metastases, disease-free survival, and overall survival at 2 years was 76%. Late complication rates were high. Grade 4 rectosigmoid, bladder, and small bowel complication rates were 49, 18, and 23% at 2 years. Late toxicity was seen earlier than expected with rectosigmoid complications observed 5 to 11.5 months (median, 8 months) after completion of treatment. CONCLUSION: Combination IFN-alpha and cisplatin produced a marked effect of enhanced radiosensitization as evidenced by 100% local tumor control and high late normal tissue complication rates. Due to the unacceptable late toxicity, its routine clinical use cannot be recommended. Further investigation is needed to determine whether a therapeutic window exists such that the use of lower doses of IFN-alpha, cisplatin, or RT can increase tumor control with more acceptable normal tissue toxicity.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1996

Reverse transcriptase-polymerase chain reaction for prostate-specific antigen may be a prognostic indicator in breast cancer.

Among women with node-negative breast cancer and small tumours, it is important to identify those with tumours that will recur, so that they may receive adjuvant therapy, while sparing those with tumours that will not recur the hazards of adjuvant treatment. A reverse transcriptase-polymerase chain reaction (RT-PCR) for prostate-specific antigen (PSA) may be used to identify circulating metastatic cells in patients with prostate cancer. Approximately 30% of breast cancer cells also produce PSA. Therefore, we tested the PSA RT-PCR assay on blood specimens from women with breast cancer. We evaluated 78 women at Mount Sinai Medical Center with histologically confirmed breast cancer. Venous blood (5 cm3) from the women was collected in ethylene diaminetetraacetic acid (EDTA)-treated collection tubes and approximately 400 ng of RNA from each sample was subjected to an RT-PCR. We were able to detect the amplified PSA fragment in 18 of 78 women with breast cancer; 7 of the 18 women with the PSA fragment had localised, small, node-negative tumours, both oestrogen receptor (ER) positive and ER negative. We could not detect the amplified PSA fragment in 20 normal women and 22 normal men. We conclude that PSA RT-PCR may be a useful method for determining the presence of circulating metastatic cells in some women with node-negative breast cancer, and therefore the potential for these women to develop recurrent disease and thus benefit from adjuvant therapy.

Adult↗

PubMed1996

Saline MR peritoneography.

OBJECTIVE: Our objective was to describe a new method for the evaluation of peritoneal surfaces in patients with intraperitoneal carcinomatosis and sarcomatosis. CONCLUSION: Fast spin-echo T2-weighted imaging in conjuction with intraperitoneally instilled saline permits detailed evaluation of peritoneal surfaces, omentum, and mesenteries. The detection of tumor implants is facilitated by their visualization against the saline background. Additionally, normal and abnormal saline distribution patterns can be identified. This technique may also be useful in predicting response to intraperitoneally instilled chemotherapy.

Female↗

PubMed1994

MRI-derived ventricular volume curves for the assessment of left ventricular function.

To assess the utility of double oblique, ECG-gated 1H magnetic resonance (MR) derived volume curves for assessing LV function, cardiac short axis images were acquired with a fast field echo technique. We applied this methodology to assess left ventricular function in three groups: normals, patients with left ventricular hypertrophy, and dilated cardiomyopathy. Six slices with 16-20 phases per RR interval were analyzed, representing the initial 75-80% of the cardiac cycle. For each slice, the endocardial border of the left ventricular (LV) chamber was manually traced. Using Simpson's rule, the total LV volume at a given phase was determined considering the traced area, thickness and position in three-dimensional space of each of the six constituent slices. The calculated volumes were plotted against time and the stroke volume, ejection fraction and cardiac output were determined. The volume vs time plots for the systolic and diastolic portions of the curve were individually fit to third degree polynomials using a least squares approximation. From the fit curves, the following data were extracted: the mean slope (dV/dT) during filling and emptying, and the time to 1/4, 1/3 and 1/2 filling and emptying. These parameters are valuable indices of the functional status of the myocardium; thus, accurate and useful estimates of LV function can be obtained using MRI derived volume curves in normal and abnormal states.

Cardiac Volume↗

PubMed1993

Altered muscle metabolism shown by magnetic resonance spectroscopy in sickle cell disease with leg ulcers.

We performed 31P magnetic resonance spectroscopy of gastrocnemius muscle at rest in 7 normal volunteers and 12 patients with sickle cell disease (7 with leg ulcers and 5 without leg ulcers but with painful crises). We measured intracellular pH and ratios of Pi to ATP, PCr to ATP and PCr to Pi (Pi = inorganic phosphate, ATP = adenosine triphosphate, and PCr = phosphocreatine). Magnetic resonance arteriograms were also performed. Significant differences were found for PCr/Pi ratios between normals and sickle cell disease patients with leg ulcers (p < 0.008). Magnetic resonance arteriograms were normal in volunteers and patients with sickle cell disease. The altered high energy phosphate metabolism in sickle cell disease with leg ulcers is consistent with muscle ischemia or hypoxia.

Adult↗

PubMedDate not supplied

Peroneal tendons: use of kinematic MR imaging of the ankle to determine subluxation.

The purpose of this study was to develop a technique for kinematic MRI of the ankle to evaluate subluxation of the peroneal tendons. A special device was used to perform incremental, passive positioning of the ankle from dorsiflexed to plantarflexed positions for the kinematic MRI examination. A fast spoiled gradient-recalled acquisition in the steady state pulse sequence was used to obtain axial images to assess the peroneal tendons during different positions of the ankle. Seven asymptomatic volunteers and five patients with suspected peroneal tendon subluxation were studied. There was no transverse displacement of the peroneal tendons observed in the asymptomatic subjects nor in two of the patients. Two patients had peroneal tendon subluxation observed on the kinematic MRI studies, and one patient had the peroneal tendons maintained in a displaced position in all ankle positions. The preliminary results suggest that kinematic MRI of the ankle is a potentially useful technique to facilitate evaluation of patients with suspected subluxation of the peroneal tendons, particularly in instances in which subluxation is position-dependent, and spontaneous reduction of the tendons may occur.

Adult↗