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Biomedical subjects

R Hashmi

Publications and source records attributed to R Hashmi.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effects of microsomal enzyme inducers on thyroid-follicular cell proliferation, hyperplasia, and hypertrophy.

The microsomal enzyme inducer (MEI), phenobarbital (PB), has been proposed to promote thyroid tumors by increasing the biotransformation and elimination of T(4), resulting in an increase in serum thyroid-stimulating hormone (TSH). In turn, TSH stimulates thyroid gland function, growth, and ultimately neoplasia. The dose-dependent effects of MEI on thyroid-follicular cell proliferation, a measure of thyroid gland growth, has not been reported. In the present study, it was hypothesized that MEIs that increase TSH would stimulate thyroid-follicular cell proliferation and the total number of thyroid-follicular cells. Male Sprague-Dawley rats were fed either a basal diet or a diet containing PB (at 300, 600, 1200, or 2400 ppm), pregnenolone-16alpha-carbonitrile (PCN) (at 200, 400, 800, or 1600 ppm), 3-methylcholanthrene (3MC) (at 50, 100, 200, or 400 ppm), or Aroclor 1254 (PCB) (at 25, 50, 100, or 200 ppm) for 7 days. PB and PCN increased TSH 65% and 95%, respectively, whereas 3MC and PCB did not appreciably affect TSH. PB and PCN increased thyroid-follicular cell proliferation 625% and 1200%, respectively, whereas 3MC and PCB did not have a consistent or appreciable effect. The total number of thyroid-follicular cells was not significantly increased by MEI treatment. In conclusion, small increases in TSH by PB and PCN produced large increases in thyroid-follicular cell proliferation, which did not result in a comparable increase in the total number of thyroid-follicular cells. Furthermore, MEI that did not increase TSH did not consistently or appreciably increase thyroid-follicular cell proliferation or cell number.

Animals↗
PubMed1999

Tc-99m-MIBI scintimammography; SPECT versus planar imaging.

UNLABELLED: This study compares single photon emission tomography (SPECT) with planar scintimammography. 16 normal, 54 benign and 80 malignant lesions were studied (total 150). 700 MBq of Tc99m-sestamibi (MIBI) was injected intravenously. Anterior supine, right and left lateral planar images were acquired in prone position at 2 hours post injection. After this a SPECT study (64 projections, 64 x 64 matrix, 30 sec/frame, anterior 180 degrees arc) was acquired in supine position. Attenuation coefficient of 0.12 and Butterworth order 5 Nyquist 0.9 filter was applied for reconstruction. A scoring system for visualization of lesions was devised with scores of 0 or 1 as negative and 2 or 3 as positive for MIBI uptake. Scores for each group of patients were added together and then compared between planar and SPECT studies. RESULTS: Planar imaging missed 10 malignant lesions while SPECT missed only 4. Ten benign lesions showed uptake of MIBI on planar imaging while 11 showed uptake on SPECT. Cumulative scores for normal and benign groups did not show any significant difference between planar and SPECT imaging. The malignant group showed significant increase in score for SPECT. Specificity, false negative fraction and positive predictive value for planar imaging were 85.7%, 14.3% and 87.5%. These values did not show any significant difference for SPECT (84.5%, 15.5% and 87.4% respectively). Sensitivity, false negative fraction and negative predictive value for planar imaging (87.5%, 12.5% and 85.7%) was significantly different (p < 0.005) than SPECT (95%, 5% and 93.7% respectively). MIBI SPECT scintimammography improves the sensitivity, false negative fraction and negative predictive value of the planar imaging. In the absence of MIBI uptake on SPECT imaging, malignancy can be ruled out with great confidence, while only uptake should be further evaluated.

Adult↗
PubMed1999

Clinical significance of a solitary hot spot in the skull.

Retrospective evaluation of bone scintigrams over the last 10 years was performed to determine the incidence of a solitary hot spot in the skull, examine its significance in patients with and without extra-skeletal malignancy, and determine if location along the suture lines is clinically significant or not. Review of the reports of bone scintigrams in 9968 patients yielded 37 (0.37%) patients with a solitary hot spot in the skull. In the group of 27 patients with extra-skeletal malignancy, the hot spot was secondary to metastasis in four patients and of a non-metastatic origin in 15. In the remaining eight patients, the cause was indeterminate. Two of the four metastatic foci were located along the suture lines. In another group of 10 patients without extra-skeletal malignancy, the cause was non-metastatic in eight patients and indeterminate in two. No significant differences between the scintigraphic features (intensity of uptake, location and relationship with sutures) of metastatic and non-metastatic foci were noted. We conclude that a solitary hot spot in the skull is rare and is predominantly benign in nature. However, in patients with known extra-skeletal malignancy, approximately 21% are secondary to a solitary bone metastasis of the skull. Location of a hot spot along the suture lines may not always be a normal variation and can represent a solitary bone metastasis.

Adolescent↗
PubMed1999

Aortoiliac and lower extremity arteries: comparison of three-dimensional dynamic contrast-enhanced subtraction MR angiography and conventional angiography.

PURPOSE: To determine the clinical feasibility of three-dimensional dynamic contrast agent-enhanced subtraction magnetic resonance (MR) angiography in patients with symptoms of lower extremity ischemia. MATERIALS AND METHODS: Twenty-three patients suspected of having lower extremity ischemia underwent three-dimensional dynamic contrast-enhanced subtraction MR angiography of the aortoiliac arteries and arteries of the lower extremity. As the reference standard, conventional angiography was also performed. For data analysis, the arterial system was divided into 10 segments. Each segment was classified as normal, mildly stenosed, moderately stenosed, severely stenosed, or occluded. RESULTS: At conventional angiography, 83 stenosed segments (14 mildly stenosed, 16 moderately stenosed, 14 severely stenosed, and 39 occluded) were identified in a total of 423 segments. For the segments with more than mild stenosis, MR angiography was 97.1% sensitive and 99.2% specific. CONCLUSION: Three-dimensional dynamic contrast-enhanced subtraction MR angiography has high sensitivity and specificity. This technique is a noninvasive alternative to conventional angiography for screening patients suspected of having lower extremity ischemia.

Aged↗
PubMed1997

Antithrombin-III for the treatment of chemotherapy-induced organ dysfunction following bone marrow transplantation.

A hypercoaguable state has been shown to follow high-dose chemotherapy for bone marrow transplantation (BMT). Deficiency of the natural anticoagulants, antithrombin III (AT-III), protein C and protein S correlate with organ dysfunction following BMT. We treated 10 patients with severe post-BMT organ dysfunction with AT-III concentrate. Indications for treatment included AT-III anticoagulant level less than 88% and life-threatening single or multiorgan dysfunction. All patients were loaded with 50 units/kg AT-III every 8 h for three doses followed by 50 units/kg/day each day for 3-12 days. Clinical improvement was seen within 1-5 days of start of therapy in all patients. Patients with veno-occlusive disease (VOD) showed a decrease in platelet consumption in nine of nine patients, resolution of hepatic tenderness in six of eight patients, and reduction of severe ascites and weight gain in four of five patients. The probability of death due to VOD and life-threatening organ dysfunction was significantly less in the AT-III-treated group when compared to a historical control group receiving the same preparative regimen (P = 0.047 and P = 0.034, respectively). Significant improvements in organ dysfunction following AT-III treatment in this small study supports a causal relationship between AT-III deficiency and post-BMT chemotherapy-induced organ dysfunction.

Adolescent↗
PubMed1997

Regional ventilation-perfusion mismatch in interstitial pneumonia. Correlation between scintigraphy and CT.

Interstitial pneumonia is one of the many causes of a scintigraphic ventilation-perfusion (V/Q) mismatch. To evaluate the morphologic features of V/Q mismatched areas in patients with interstitial pneumonia, we correlated the findings on lung scintigraphy using Kr-81m and Tc-99m MAA with CT scan findings. Of 41 patients, 20 (49%) had a high V/Q mismatched areas. All of these areas corresponded to cystic air spaces shown on CT, and most of the showed a honeycomb pattern. Ventilation-perfusion matched defects were seen in 23 patients (56%). The matched defects corresponded to cystic air spaces (honeycomb or bullous changes) or lung attenuation changes of varying degrees on CT. Cystic air spaces with high V/Q mismatch are considered to be normally ventilated. To distinguish mismatched areas of interstitial pneumonia from areas of pulmonary embolism, it may be necessary to compare scintigraphic findings with CT.

Adult↗
PubMed1994

Safety of pharmacological (intravenous dipyridamole) stress for Thallium-201 perfusion imaging in patients with coronary artery disease unable to exercise.

Exercise Thallium-201 myocardial perfusion imaging is a sensitive technique for detection of CAD. However, in patients unable to perform exercise pharmacological stress with intravenous dipyridamole can be used to dilate coronaries. Out of 125 patients (21 men and 104 women; mean age 52.03 years) evaluated, 110 were considered to be unable to perform adequate stress by their physician while remaining 15 had LBBB. One hundred and seven patients had chest pain with or without a remote MI while 18 individuals were clinically asymptomatic but had ECG abnormalities. Intravenous dipyridamole was administered at a rate of 0.142 mg/kg/min for 4 min. After 3 min an i.v. bolus of T1-201 was given. Diffuse or occipital headache of mild to moderate intensity occurred in 50 (40%) cases; 39 patients experienced chest pain and had either a positive thallium scan (26 cases) suggestive of CAD or a normal thallium study (15 cases). Complete relief from dipyridamole induced symptoms was brought by i.v. aminophylline and sublingual nitrate in 51 of 54 cases (94%) and 11 of 18 (61%) respectively. We, therefore, conclude: 1) i.v. dipyridamole-thallium scintigraphy offers a safe, effective and reliable method for evaluating CAD in those who are unable to perform adequate exercise and 2) parenteral aminophylline is very effective antidote to dipyridamole.

Aminophylline↗
PubMed1994

Evaluation of coronary artery disease using locally prepared myocardial perfusion agent 99mTc-MIBI.

Technetium (99mTc) labelled isonitrile complexes are recently introduced agents for imaging myocardial perfusion and viability. This study presents the first clinical experience with a locally prepared agent 99mTc methoxy iso butyl isonitrile (MIBI). Sixteen randomly selected cases (M:F 14:2, mean age 48 years) were included; clinically 4 patients were asymptomatic, 6 had history of MI while remaining 6 had angina with no previous incidence of MI. Separate injections were given for rest and stress studies either on the same day (9 cases) or on separate days (7 cases). All patients were stressed according to the Modified Bruce Protocol and 99mTc MIBI was injected at peak stress. Early blood pool and delayed static images showed reasonably good localization of MIBI in the viable myocardium and image quality was also comparable to what has been reported in literature. Scans were negative for any perfusion abnormality in 6 cases, positive for single vessel disease in 6 and for two vessels disease in 4 patients. We conclude that the locally prepared 99mTc MIBI has optimal sensitivity and pharmacokinetic properties for myocardial imaging and detection of CAD. Moreover the local preparation would also entail considerable foreign exchange saving.

Adult↗
PubMedDate not supplied

Traction injuries of the brachial plexus: signal intensity changes of the posterior cervical paraspinal muscles on MRI.

PURPOSE: Our goal was to evaluate MR signal intensity change of the posterior cervical paraspinal muscles in brachial plexus traction injuries to determine the value of this finding in the diagnosis of nerve root avulsion. METHOD: MR images of 11 consecutive patients, 7 with nerve root avulsion and 4 without nerve root avulsion, were retrospectively analyzed, focusing on the signal intensity of the paraspinal muscles. RESULTS: Among the seven patients with nerve root avulsion, T2- or T2*-weighted MR images showed increased signal intensity in the deep posterior paraspinal muscles in five and traumatic meningocele in four. The signal intensity of the posterior paraspinal muscles was normal in all patients without nerve root injuries. CONCLUSION: MR signal intensity change in the deep posterior cervical paraspinal muscles is related to denervation and suggests the presence of nerve root avulsion.

Accidents, Traffic↗
PubMedDate not supplied

Peripheral nerve intraneural ganglion cyst: MR findings in three cases.

We present MR findings of three cases of surgically proved intraneural ganglion cysts involving the common peroneal nerve (two patients) and ulnar nerve (one patient). The lesions were located along the course of the involved nerve and situated close to a joint. MRI demonstrated the cystic nature and extent of the lesions with clear definition of the anatomic relationship of the lesions to the surrounding structures.

Adult↗