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Biomedical subjects

Ohad Cohen

Publications and source records attributed to Ohad Cohen.

At least 19 recordsLinked to original sources
PubMed2006

Time trends of incidence rates of thyroid cancer in Israel: what might explain the sharp increase.

BACKGROUND: Worldwide changes in the incidence, histological type, and prognosis of thyroid cancer (TC) have been observed. Regional differences in the spectrum of TC may be related to genetic factors, ionizing radiation, lifestyle, and nutritional iodine, as well as to the availability of medical services. METHODS: Analysis of records of 5864 TC patients (diagnosed between 1982 and 2001), retrieved from the Israel National Cancer Registry. RESULTS: The age-standardized incidence rate (ASR per 100,000 persons) of TC among Jewish women in 2001 was 12.45 (higher than generally reported in the world) and 3.68 among Jewish men. There was a significant increase in the ASR for TC between 1982 and 2001 in the Jewish population (by 101% among women and by 25% among men, p < 0.01 for both), mainly due to papillary carcinoma. TC incidence increased in the non-Jewish population from 2.33 to 6.02 in women (p < 0.05) and from 1.13 to 2.49 in men (p > 0.05). TC incidence was similar among immigrants from Europe and America arriving in Israel before 1990 or after 1990 for both genders. An improved 5-year survival was noted in patients diagnosed between 1992 and 1996 in comparison to patients diagnosed earlier: 1982-1986 (86% versus 78%, p < 0.01). CONCLUSIONS: A marked increase in TC incidence over the last two decades (mainly due to papillary carcinoma) has been noted in different Israeli subpopulations, being the highest in Jewish women. The increase trends were similar regardless of gender or ethnicity. The reasons for this rise in TC incidence and improvement in the survival are probably multifactorial and may relate partly to increased diagnostic vigilance and changes in clinical practice.

Africa↗
PubMed2006

Scanning electron microscopy of thyroid cells under fully hydrated conditions--a novel technique for a seasoned procedure: a brief observation.

Technical information for handling fine-needle aspiration samples from thyroid lesions for WETSEM electron microscopy is presented. The use of wet SEM technology maintains cytological features of the thyroid cells, in the atmospheric electronic microscope chamber without the need for solidification. Images are presented from normal and pathological thyroid specimens showing subcellular elements unavailable to the cytopathologist by light microscopy. Of 24 samples, 18 were adequate for clinical evaluation. In 16 of these 18 specimens, we could find features compatible with the final histological or cytological diagnosis (post-hoc). In two cases, the cell features were too unique to be interpretable. Because this procedure is relatively simple, there is potential for the use of this technology as an adjunct to light microscopy in clinical and research settings.

Adult↗
PubMed2006

Longitudinal assessment of insulin sensitivity in pregnancy. Validation of the homeostasis model assessment.

OBJECTIVE: To validate the use of the homeostasis model assessment (HOMA) for measurement of insulin sensitivity in obese women during gestation and the postpartum period. DESIGN: Three consecutive measurements of insulin resistance (IR) were performed during and after pregnancy to compare the homeostasis model assessment insulin sensitivity index (HOMA-IR) to glucose utilization rates obtained during hyperinsulinaemic euglycaemic clamps (G(Rd)). PATIENTS: Six obese women (mean second trimester BMI = 30.4 kg/m(2)) with normal glucose tolerance were studied during the second and third trimesters of pregnancy and once in the postpartum period. Thus, there were a total of 18 measurements for analysis. RESULTS: Correlations between the rate of glucose disappearance (G(Rd)) (the gold standard) and the HOMA-derived metabolic parameters of insulin sensitivity were significant, with a multiple R(2) of 43.5% (P = 0.003). However, when controlling for variations between patients using dummy variables, we observed that one patient differed from the other five in the relationship between G(Rd) and HOMA-IR. Applying this regression we obtained a R(2) of 72.6% (P < 0.001). When the regression constant was omitted, we observed that the individual trends during pregnancy and postpartum in two patients differed statistically from the other patients between the two assessments, and we obtained a multiple R(2) of 97.3% (< 0.001). CONCLUSIONS: HOMA estimation of insulin resistance is appropriate for use during both the second and third trimesters of pregnancy and postpartum in obese women with normal glucose tolerance. It lacks sensitivity for the evaluation of individuals, where more precise measures of insulin sensitivity should be utilized.

Adult↗
PubMed2006

Low-dose recombinant human thyrotropin-aided radioiodine treatment of large, multinodular goiters in elderly patients.

OBJECTIVE: We aimed to assess low-dose recombinant human thyroid-stimulating hormone (rhTSH)-aided, fixed-activity radioiodine therapy of large, multinodular goiters (MNGs) in elderly patients with comorbidities. DESIGN: This was a short-term, observational study. METHODS: We measured 24-h thyroid radioiodine uptake (RAIU) of 2 microCi 131-iodine at baseline and 24 h after intramuscular injection of 0.03 mg rhTSH in 17 patients (aged 60-86 years, 12 women), who subsequently received 30 mCi 131-iodine 24 h after an identical rhTSH injection. TSH and free thyroxine (FT4) were measured at baseline and days 10, 30 and 90 after therapy. Thyroid volume was assessed by computed tomography at baseline and day 180. RESULTS: rhTSH, 0.03 mg, significantly increased mean 24-h thyroid RAIU from 25.8% +/- 10.3% to 43.3% +/- 8.4% (68% relative increase; t(16) = -8.43, P < 0.001). The proportion of patients overtly or subclinically hyperthyroid (TSH < 0.5 mU/l) decreased from 71% (12/17) at baseline to 19% (3/16) at 3 months. Mean serum FT4 peaked at slightly above normal range, 25.9 +/- 7.7 pmol/l (46% over baseline) and was 21% under baseline levels at 3 months. Mean estimated thyroid volume fell 34% from baseline to 6 months (170.0 +/- 112.8 to 113.1 +/- 97.5 ml; P < 0.01). Symptomatic relief, improved well-being, and/or reduction or elimination of antihyperthyroid medication were seen in 76% of patients. Three (18%) patients had transient neck pain or tenderness, or palpitations; one had transient asymptomatic thyroid enlargement; and three (18%) became hypothyroid by 3 months. CONCLUSIONS: Intramuscular rhTSH, 0.03 mg, followed 24 h later by 30 mCi 131-iodine, is a safe, effective and convenient treatment for MNG in elderly patients with comorbidities.

Aged↗
PubMed2006

Prediction of postprandial glycemic exposure: utility of fasting and 2-h glucose measurements alone and in combination with assessment of body composition, fitness, and strength.

OBJECTIVE: To determine the best predictors of total postprandial glycemic exposure and peak glucose concentrations in nondiabetic humans. RESEARCH DESIGN AND METHODS: Data from 203 nondiabetic volunteers who ingested a carbohydrate-containing mixed meal were analyzed. RESULTS: Fasting glucose and insulin concentrations were poor predictors of postprandial glucose area above basal (R2 = approximately 0.07, P < 0.001). The correlation was stronger for 2-h glucose concentration (R2 = 0.55, P < 0.001) and improved slightly but significantly (P < 0.001) with the addition of fasting glucose, insulin, age, sex, and body weight to the model (r2 = 0.58). The 2-h glucose concentration also predicted the peak glucose concentration (R2 = 0.37, P < 0.001) with strength of the prediction increasing (P < 0.001) modestly with the addition of fasting glucose, insulin, age, sex, and body weight to the model (R2 = 0.48, P < 0.001). On the other hand, addition of measures of body function and composition did not improve prediction of total glycemic exposure or peak glucose concentration. CONCLUSIONS: Isolated measures of fasting or 2-h glucose concentrations alone or in combination with more complex measures of body composition and function are poor predictors of postprandial glycemic exposure or peak glucose concentration. This may explain, at least in part, the weak and at times inconsistent relationship between these parameters and cardiovascular risk.

Adult↗
PubMed2005

Elevated serum uric acid levels in gestational hypertension are correlated with insulin resistance.

The purpose of this study was to assess a possible correlation between insulin resistance and uric acid levels in gestational hypertension (GH) and preeclampsia. Fourteen pregnant, nondiabetic women with either GH (n = 7) or preeclampsia (n = 7) and nine pregnant healthy controls in the third trimester were enrolled onto the study. Fasting serum was collected and insulin sensitivity was determined by Homeostasis Model Assessment based on the algorithm developed by Turner and colleagues. Serum samples were also analyzed for creatinine and uric acid levels. Insulin resistance and uric acid levels were compared between hypertensive and control pregnant women, and the association between these two variables was calculated. There were no significant differences in mean age, weight, body mass index, and glucose challenge test between all hypertensive patients and controls. Significant differences were revealed in insulin sensitivity between hypertensive and nonhypertensive pregnant women (45 +/- 31.2% vs. 79.7 +/- 33%; p = 0.018). In our study, uric acid levels were not significantly higher for hypertensive patients (5.46 +/- 0.85 vs. 4.53 +/- 1.4 mg/dL in controls; p = 0.06). The elevated serum uric acid levels were highly correlated to insulin resistance in patients with GH. In contrast, uric acid levels did not correlate with insulin sensitivity in patients with preeclampsia and controls. Insulin resistance is associated with the elevated uric acid levels found in nonproteinuric gestational hypertensive disease.

Adult↗
PubMed2005

Successful pregnancy after unilateral adrenalectomy in a case of primary pigmented adrenocortical disease.

We describe a case of successful pregnancy in a patient with primary pigmented nodular adrenocortical disease. Unilateral adrenalectomy was performed pre-conception as treatment for the patient's bilateral adrenal disease. She later delivered a healthy infant by cesarean section at week 38 of gestation. There was no evidence of either hyper- or hypo-cortisolism during the pregnancy. The unilateral laparoscopic adrenalectomy was successful in controlling her hypercortisolism during the ensuing pregnancy, and might provide a valid (albeit temporary) solution in similar situations.

Adrenal Cortex Diseases↗
PubMed2005

Post-surgical use of radioiodine (131I) in patients with papillary and follicular thyroid cancer and the issue of remnant ablation: a consensus report.

OBJECTIVE: To determine, based on published literature and expert clinical experience, current indications for the post-surgical administration of a large radioiodine activity in patients with differentiated thyroid cancer. DESIGN AND METHODS: A literature review was performed and was then analyzed and discussed by a panel of experts from 13 European countries. RESULTS: There is general agreement that patients with unifocal microcarcinomas = 1 cm in diameter and no node or distant metastases have a <2% recurrence rate after surgery alone, and that post-surgical radioiodine confers recurrence and cause-specific survival benefits in patients, strongly suspected of having persistent disease or known to have tumor in the neck or distant sites. In other patients, there is limited evidence that after complete thyroidectomy and adequate lymph node dissection performed by an expert surgeon, post-surgical radioiodine provides clear benefit. When there is any uncertainty about the completeness of surgery, evidence suggests that radioiodine can reduce recurrences and possibly mortality. CONCLUSION: This survey confirms that post-surgical radioiodine should be used selectively. The modality is definitely indicated in patients with distant metastases, incomplete tumor resection, or complete tumor resection but high risk of recurrence and mortality. Probable indications include patients with tumors >1 cm and with suboptimal surgery (less than total thyroidectomy or no lymph node dissection), with age <16 years, or with unfavorable histology.

Carcinoma, Papillary, Follicular↗
PubMed2005

Blood glucose awareness training helps return insulin-treated aviators to the cockpit.

Insulin-treated diabetes mellitus has traditionally been considered disqualifying for aviation duties, the major concern being the risk of hypoglycemia. This phenomenon may lead to impaired judgment and even loss of consciousness, potentially leading to a mishap. Blood glucose awareness training has been advanced as a strategy to avoid hypoglycemia by teaching individuals to use the appearance of autonomic and neuroglycopenic symptoms as indicators of decreasing blood glucose levels. We present two military aviators with newly diagnosed type 1 diabetes mellitus who were returned to flying duty in a multicrew aircraft. Blood glucose awareness training was used as a tool for the education of these aviators regarding the early signs of hypoglycemia in order to avoid development of more significant hypoglycemia. These cases attest to the importance of blood glucose awareness training in the return of diabetic patients to the cockpit.

Adult↗
PubMed2004

Follow-up of low-risk patients with differentiated thyroid carcinoma: a European perspective.

OBJECTIVE: Because differentiated (follicular and papillary) thyroid cancer (DTC) may recur years after initial treatment, the follow-up of patients with DTC is long term. However, this population has changed, with more individuals being discovered at an earlier stage of the disease, so that previous follow-up protocols based mostly on data from high-risk patients no longer apply. We sought to develop an improved protocol for the follow-up of low-risk patients with DTC based on the findings of recent studies. METHODS: We analysed recent literature on the follow-up of DTC. RESULTS: Recent large studies have produced three important findings: (i) in patients with low-risk DTC with no evidence of disease up to the 6- to 12-month follow-up, diagnostic whole-body scan adds no information when serum thyroglobulin (Tg) is undetectable and interference from anti-Tg antibodies is absent; (ii) use of recombinant human thyroid-stimulating hormone to aid Tg measurement is effective and provides greater safety, quality-of-life and work productivity than does levothyroxine withdrawal with its attendant hypothyroidism; and (iii) ultrasonography performed by an experienced operator is the most sensitive means of detecting neck recurrences of DTC. CONCLUSIONS: We present a revised follow-up protocol for low-risk patients taking into account the above findings. This protocol should help clinicians enter a new era of monitoring characterized by greater safety, simplicity, convenience and cost savings.

Adenocarcinoma, Follicular↗
PubMed2004

Compliance with follow-up and the informative value of diagnostic whole-body scan in patients with differentiated thyroid carcinoma given recombinant human TSH.

OBJECTIVE: Protocols for monitoring patients with differentiated thyroid cancer (DTC) include measurement of serum Tg and, for most patients, whole-body scan (WBS) with low radioiodine activities ('diagnostic' WBS). Recently, recombinant human thyroid-stimulating hormone (rhTSH) has become available to provide the TSH stimulation necessary for these procedures, whilst avoiding thyroid hormone withdrawal and hypothyroid complications. In addition, the inclusion of diagnostic WBS in DTC follow-up has recently become controversial. We have assessed the compliance with withdrawal-aided monitoring and the informative value of diagnostic WBS in consecutive tertiary referral center patients. DESIGN: Forty-eight patients received rhTSH (0.9 mg) in two consecutive daily injections, with radioiodine administration 24 h, diagnostic WBS 48 h, and serum Tg testing prior to and 72 h later. METHODS: Compliance with withdrawal-aided monitoring was assessed with a questionnaire provided by the referring physician, patient record analysis, and patient interview. The informative value of diagnostic WBS was assessed by comparing findings against serum Tg measurements in light of physical and other radiological examinations. RESULTS: Forty of the forty-eight patients were female, the mean age was 43.9 years and the median follow-up from diagnosis was 4.5 years (range 1-19 years). Twenty-seven (56%) patients were compliant and 12 (25%) were non-compliant; compliance was not known in nine. Of 17 patients with clinically suspicious or significant findings on any available modality, four had uptake outside the thyroid bed on WBS but stimulated Tg <2.5 ng/ml on immunometric assay, while five had a negative WBS with serum Tg >2.5 ng/ml. CONCLUSIONS: Thyroid hormone withdrawal substantially impairs, and rhTSH administration substantially promotes, compliance with DTC monitoring. rhTSH-aided WBS is informative and should be included in the follow-up of unselected patients with DTC.

Adult↗
PubMed2004

Follow-up and management of differentiated thyroid carcinoma: a European perspective in clinical practice.

As differentiated (follicular and papillary) thyroid cancer (DTC) may recur years after initial treatment, follow-up of patients with DTC is long term. However, this population has changed, with more individuals being discovered at an earlier stage of disease, so that previous follow-up protocols based mostly on data from high-risk patients no longer apply. We have proposed, in a previous issue of this Journal, an improved protocol for the follow-up of low-risk patients with DTC based on the findings of recent studies. We report here the case of a paradigmatic patient with papillary thyroid carcinoma, with the goal of illustrating the benefits of applying this algorithm in routine clinical practice. We also offer expanded and additional comments on various issues in the management of DTC.

Adult↗
PubMed2003

Serial in utero ultrasonographic measurements of the fetal thyroid: a new complementary tool in the management of maternal hyperthyroidism in pregnancy.

OBJECTIVE: Treatment of maternal hyperthyroidism during pregnancy is complicated by the lack of readily available measures of the thyroid status of the fetus. The aim of this study is to describe the use of serial in utero ultrasound measurements of fetal thyroid in patients being treated for Graves' disease in pregnancy. METHODS: Over a 24-month period, all pregnant women with Graves' disease attending our special Fetal Thyroid Unit were followed. Maternal thyroid status was assessed by thyroid function tests. Fetal thyroid size was measured serially by transvaginal ultrasonography between 14 and 17 weeks of gestation and by abdominal ultrasonography between 18 and 37 weeks of gestation in 20 women with Grave's disease. RESULTS: In 15 fetuses, thyroid width and circumference were within the 95% confidence interval of the normal population. In five fetuses, thyroid size was above the 95th percentile for gestational age. In three of them, thyroid size decreased concurrently with a decrease in maternal thionamide dosage, reaching normal range. These three fetuses were born euthyroid. In two fetuses, thyroid size was unaffected by a decrement in maternal drug dosage. Both had neonatal thyrotoxicosis at birth. CONCLUSIONS: Serial in utero ultrasonography measuring fetal thyroid size in mothers with Graves' disease can serve as an effective noninvasive tool for the early detection of enlarged fetal thyroid. These findings can be used to monitor the maternal antithyroid drug dosage, thereby preventing intrauterine hypothyroidism in some cases. When a dosage reduction does not cause a decrease in fetal thyroid size, transplacental passage of thyroid-stimulating antibodies causing fetal thyrotoxicosis should be suspected.

Adult↗
PubMed2003

Multidisciplinary intervention for control of diabetes in patients undergoing coronary artery bypass graft (CABG).

In Israel, as elsewhere, diabetes mellitus is highly prevalent among patients undergoing coronary artery bypass graft (CABG). The bulk of evidence, derived retrospectively, suggests that poor control of diabetes predisposes to complications of CABG and increases mortality; but the findings in a number of studies fail to support that impression. Anticipating a prospective investigation designed to resolve this issue, we have carried out a preliminary study of 147 consecutive patients with diabetes who were hospitalized for elective CABG during 1998. Our objective was to determine how well and how often diabetes could be controlled in accordance with selected metabolic goals in the brief interval between hospital admission and surgery and during the operation itself and in the postoperative period. The task was undertaken by a multidisciplinary team, in cooperation with the Department of Cardiac Surgery. The metabolic goals were: fasting blood glucose consistently between 65-140 mg/dl before and after surgery and 120-180 mg/dl at the time of surgery; and postprandial blood glucose consistently <180 mg/dl. These goals were achieved in 18.1% of fasting blood glucose measurements before and after surgery, 22.1% of preprandial and 14.6% of postprandial blood glucose levels consistently <180 mg/dl. There were no clinical episodes of hypoglycemia. Due to the low incidence of major infection related complications (deep sternal wound infection in only 3 patients (2.0%)) no significant statistical conclusions on the relations between glucose control and these complications could be drawn. The means of all values of FBG and of hemoglobin A1c were significantly higher among patients with complications (n=49) than in those without (P=0.01).

Aged↗
PubMed2003

Glucose correlation with light scattering patterns--a novel method for non-invasive glucose measurements.

To correlate occlusion red near-infrared spectroscopy technology with intravenous and interstitial glucose levels, occlusion red near-infrared spectroscopy and glucose levels were measured in five subjects with diabetes mellitus during a stepped hyperinsulinemic hypoglycemic clamp. Validation was achieved using a standard error grid and linear correlations. During hyperinsulinemic hypoglycemic clamp linear correlation was significant at r = 0.836, and the intercept was 43.3 mg/dL. Of the glucose measurements, 94.3% were assigned to zones A and B of the standard error grid, the zones of the greatest therapeutic relevance. Expected interference from serum triglycerides, catecholamines, and cortisol was not apparent. These results demonstrate the applicability of occlusion red near-infrared spectroscopy for in vivo glucose monitoring. The technology has implications for continuous non-invasive glucose sensing.

Adult↗