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Biomedical subjects

M Klain

Publications and source records attributed to M Klain.

At least 37 records · Page 2Linked to original sources
PubMed1996

Future directions for resuscitation research. I. Advanced airway control measures.

The efficacy of 'basic' airway control without equipment, using the combination of backward tilt of the head, forward displacement of the mandible, and separation of lips and teeth (i.e. the triple airway maneuver) has been well established. Direct mouth-to-mouth and mouth-to-nose ventilation must continue to be taught to the public. Further improvements are needed for pocket-size mouth-to-mouth barriers to combat infection risks. Dissemination of appropriate information on disease transmission is needed to ensure ventilation by health professionals, using exhaled air ventilation adjuncts and other devices. Much knowledge exists about the pathophysiology of airway obstruction. For patients in coma or anesthesia with airway obstruction, which resists basic airway control measures and standard tracheal intubation, available 'advanced' airway control measures should be mastered and improved. Preparedness for advanced airway control measures differs between elective management of the anticipated difficult airway for anesthesia and emergency airway control with unanticipated difficulties encountered during the ordinary sequential application of measures. Challenges include education research and development of new devices. For airway clearing, pharyngeal intubation, difficult tracheal intubation, cricothyrotomy, transtracheal jet ventilation and emergency use of oxygen - what could and should be taught, to whom, and how? Which new devices and training systems should be developed? The most important alternative to orotracheal or nasotracheal intubation recommended for the development of novel devices and teaching methods for health professionals, are cricothyrotomy (with wide enough airway to also enable spontaneous breathing of air), and translaryngeal or transtracheal oxygen jet ventilation. We recommend openness in communication and joint planning between anesthesiologists, emergency care providers, and appropriate educators, engineers and industries.

Cardiopulmonary Resuscitation↗
PubMed1996

The role of radiolabeled somatostatin analogs in adrenal imaging.

We investigated the role of radiolabeled somatostatin analogs (SAs) in adrenal imaging. We evaluated 15 patients (6 men and 9 women, mean age 47 +/- 17 years) with imaging-detected adrenal tumors. Patient population was divided into two groups on the basis of the nature of adrenal lesions. Group 1 consisted of patients with benign adrenal lesions (n = 10). Group 2 consisted of patients with malignant adrenal lesions (n = 5). Pathology examinations were obtained in 13 cases: 7 pheochromocytomas, 2 adenomas, 2 cysts, 1 carcinoma, and 1 fibro-histiocytoma. One patient had a proven diagnosis of non-small-cell lung cancer associated with the presence of a right adrenal mass. The last patient had a clinical diagnosis of Werner syndrome associated with the presence of a large left adrenal mass. All patients underwent scientigraphic studies using radiolabeled SAs, of which indium-111 (In-111) pentetreotide was used in 11 cases and technetium-99m (Tc-99m)-labeled peptides (P-587 or P-829) were used in the remaining four cases. No significant labeled SAs uptake was observed in the majority (8 of 10, 80%) of the benign adrenal lesions (Group 1); however, increased uptake was found in two benign pheochromocytomas. Conversely, significant labeled SAs uptake was observed in the majority (4 of 5, 80%) of the malignant adrenal lesions (Group 2); however, the last lesion (carcinoma) did not show abnormal uptake. Results of this study show that the majority of benign adrenal tumors do not concentrate radiolabeled SAs; conversely, the majority of malignant adrenal lesions show significant SAs uptake, suggesting the presence of somatostatin receptors. This finding may allow the use of somatostatin as a treatment agent in malignant adrenal tumors. Thus, the main role of labeled SAs in adrenal imaging consists of lesion characterization rather than tumor detection and localization.

Adrenal Gland Neoplasms↗
PubMed1996

Suspended animation for delayed resuscitation.

Suspended animation is defined as the therapeutic induction of a state of tolerance to temporary complete systemic ischemia, i.w., protection-preservation of the whole organism during prolonged circulatory arrest ( > or = 1 hr), followed by resuscitation to survival without brain damage. The objectives of suspended animation include: a) helping to save victims of temporarily uncontrollable (internal) traumatic (e.g., combat casualties) or nontraumatic (e.g., ruptured aortic aneurysm) exsanguination, without severe brain trauma, by enabling evacuation and resuscitative surgery during circulatory arrest, followed by delayed resuscitation; b) helping to save some nontraumatic cases of sudden death, seemingly unresuscitable before definite repair; and c) enabling selected (elective) surgical procedures to be performed which are only feasible during a state of no blood flow. In the discussion session, investigators with suspended animation-relevant research interests brainstorm on present knowledge, future research potentials, and the advisability of a major research effort concerning this subject. The following topics are addressed: the epidemiologic facts of sudden death in combat casualties, which require a totally new resuscitative approach; the limits and potentials of reanimation research; complete reversibility of circulatory arrest of 1 hr in dogs under profound hypothermia ( < 10 degrees C), induced and reversed by portable cardiopulmonary bypass; the need for a still elusive pharmacologic or chemical induction of suspended animation in the field; asanguinous profound hypothermic low-flow with cardiopulmonary bypass; electric anesthesia; opiate therapy; lessons learned by hypoxia tolerant vertebrate animals, hibernators, and freeze-tolerant animals (cryobiology); myocardial preservation during open-heart surgery; organ preservation for transplantation; and reperfusion-reoxygenation injury in vital organs, including the roles of nitric oxide and free radicals; and how cells (particularly cerebral neurons) die after transient prolonged ischemia and reperfusion. The majority of authors believe that seeking a breakthrough in suspended animation is not utopian, that ongoing communication between relevant research groups is indicated, and that a coordinated multicenter research effort, basic and applied, on suspended animation is justified.

Animals↗
PubMed1996

[Positron emission tomography (PET) with fludeoxyglucose F 18 in the study of adrenal masses: comparison of benign and malignant lesions].

In this study, 15 patients (4 men and 11 women, mean age: 50 +/- 13 years) with unilateral adrenal masses detected on ultrasound (US), Computed Tomography (CT) and/or Magnetic Resonance (MR) studies were submitted to positron emission tomography (PET) with fluorine-18 deoxyglucose (FDG). Histology demonstrated 3 adenomas, 1 myelolipoma, 1 angiolipoma, 1 neurinoma, 1 cyst, 1 malignant pheochromocytoma, 4 carcinomas and 3 metastases. The patient population was divided into two groups. Group 1 (n = 7) consisted of benign adrenal lesions. Group 2 consisted of malignant adrenal tumors. Lesion measurements were performed on the basis of the results of US, CT and/or MR images. In Group 1, no FDG uptake was observed in adrenal masses. Conversely, in Group 2 adrenal lesions showed abnormally increased FDG uptake, suggesting high glucose tumor metabolism. No significant difference in lesion size was observed between Groups 1 and 2 (5.6 +/- 4.0 vs 6.3 +/- 3.0 cm). Furthermore, in 6 patients of Group 2, total body PET images showed abnormal FDG uptake in extra-adrenal locations, such as chest (n = 2) and abdominal (n = 5) lymph nodes, lungs (n = 6), liver (n = 5), pancreas (n = 1), bone (n = 1) and muscle (n = 1) tissues. In conclusion, the results of this study suggest that PET imaging with FDG can characterize adrenal masses. In particular, abnormally increased FDG uptake in adrenal malignancies allows to differentiate these abnormalities from benign lesions. Furthermore, total body imaging PET can identify extra-adrenal tumor sites in patients with malignant tumors.

Adrenal Gland Neoplasms↗
PubMed1995

Technetium-99m-tetrofosmin regional myocardial uptake at rest: relation to severity of coronary artery stenosis in previous myocardial infarction.

UNLABELLED: The aim of this study was to assess the potential role of 99mTc-tetrofosmin cardiac tomography in detecting totally occluded or severely stenosed coronary arteries. METHODS: Thirty-three patients (32 men, 1 woman; mean age, 52 +/- 9 yr) with chronic coronary artery disease (CAD) and left ventricular dysfunction (ejection fraction 40% +/- 12%) underwent resting 99mTc-tetrofosmin SPECT and coronary arteriography within 2 wk. Regional distribution of 99mTc-tetrofosmin activity was compared with the coronary anatomy. Tracer uptake was quantitatively analyzed in 22 segments for each patient. The activity in each segment was expressed as a percent of the peak activity. RESULTS: A significant relationship between the degree of coronary artery stenosis and 99mTc-tetrofosmin uptake was observed (p = -0.64, p < 0.001). Technetium-99m-tetrofosmin uptake was lower (p < 0.001) in segments with 100% coronary occlusion with poor collateral flow (53% +/- 17%) compared to segments supplied by a vessel with 50%-99% coronary stenosis (75% +/- 20%) or a normal noncritically stenosed artery (85% +/- 10%). Furthermore, 99mTc-tetrofosmin uptake was lower (p < 0.01) in segments with 100% coronary occlusion with poor (53% +/- 17%) compared to those with good collateral flow (70% +/- 20%). CONCLUSION: These results demonstrate that quantitative analysis of resting 99mTc-tetrofosmin regional uptake detects the majority of segments supplied by occluded coronary arteries with poor collateral flow and suggest that this tracer may be helpful in the diagnosis of acute myocardial infarction.

Adult↗
PubMed1995

Technetium-99m-tetrofosmin imaging of differentiated mixed thyroid cancer.

This report describes the accurate localization of metastatic lesions in a patient with differentiated mixed thyroid cancer using 99mTc-tetrofosmin imaging. A 66-yr-old women with a cytological diagnosis of follicular thyroid cancer associated with a large amount of goiter changes was studied by 99mTc-tetrofosmin total-body scintigraphy. No significant tetrofosmin uptake was observed in the thyroid nodules, which mainly showed goiter abnormalities. Abnormal increased tetrofosmin uptake, however, was found in metastatic tumor lesions located in the cervical and dorsal spine as well as in the left lower chest wall and lungs. In conclusion, 99mTc-tetrofosmin, a new radiopharmaceutical proposed for myocardial perfusion imaging, may be useful in patients with thyroid cancer.

Aged↗
PubMed1995

[Scintigraphic characterization of expansive lesions located in the adrenals. Comparison with magnetic resonance imaging].

In this study, 35 patients (11 men and 24 women, mean age 47 +/- 16 years) with unilateral adrenal masses underwent nor-cholesterol (nor-Chol) (n = 11), metaiodobenzylguanidine (MIBG) (n = 15) or nor-Chol and MIBG (n = 9) radionuclide studies. In all patients Magnetic Resonance (MR) adrenal imaging was also performed. In 19 (54%) patients, no laboratory abnormalities of adrenal function were observed. In the other 16 (46%) patients, adrenal hyperfunction was found. In 21 lesions, histology showed 10 pheochromocytomas (Pheos), 6 adenomas, 3 metastases, 1 cyst and 1 nodular focal liver hyperplasia. In the remaining 14 lesions, increased cortisol (n = 4) or aldosterone (n = 2) levels and/or intense nor-Chol uptake (n = 14) were considered suggestive of adenoma. Diagnostic accuracy of both nor-Chol and MIBG radionuclide studies in correctly identifying adenoma or Pheos was 100%. Conversely, qualitative MR signal intensity (SI) analysis on T2-weighted images did not allow to accurately distinguish lesions of different nature. In particular, 10 Pheos, 8 adenomas, 3 mestastasis and 1 cyst clearly showed on T2-weighted images higher SI than the liver; 5 adenomas had a slight higher SI; the remaining lesions (7 adenomas and 1 liver hyperplasia) exhibited low SI. In conclusion, adrenal scintigraphy using nor-Chol or MIBG allows to identify adenomas and Pheos, respectively. Conversely, qualitative MR SI analysis cannot differentiate different adrenal lesion (Pheos, adenoma, metastasis and cyst) and yields heterogeneous results in adenomas.

3-Iodobenzylguanidine↗
PubMed1995

111In-pentetreotide scintigraphy in the post-thyroidectomy follow-up of patients with medullary thyroid carcinoma.

Local and lymphnodal recurrences of medullary thyroid carcinoma (MTC) in thyroidectomy patients with elevated plasma levels of calcitonin and/or CEA can be detected using 111In-pentetreotide (Octreoscan: OCT) scintigraphy, although the sensitivity of this technique in localizing an intrathyroid recurrence of tumor is affected by the low target/non-target uptake ratio. The survival rate of patients with MTC, who have undergone thyroidectomy and who show evidence of a rise in plasma levels of calcitonin and/or CEA is closely linked to the number and localization of the metastases. However the role of conventional imaging techniques (X-rays, US, CT, and MR) in the follow-up after thyroidectomy is controversial. Numerous radiocompounds are currently being used to detect local and distant recurrences of MTC. The present study evaluated OCT and pentavalent 99mTc-dimercapto-succinic-acid (99mTc-DMSA-V) scintigraphy performed in 13 patients with a histologic diagnosis of MTC and in one with MEN 2A, all of whom had undergone thyroidectomy between 3 months and 15 years before. The patients also underwent 123I (NaCI) scintigraphy to evaluate the sites and extension of thyroidal remnants. 111In-pentetreotide scintigraphy was positive in 9/14 patients (64%); the 99mTc-DMSA-V was positive in 5/14 patients (35%). 111In-pentetreotide scintigraphy recognized 18 sites of abnormal uptake (12 in the neck); 9mmTc-DMSA-V detected 9 MTC recurrences in the same patients. In conclusion, 111In-OCT scintigraphy represents, in the authors' experience, a useful method, more sensitive than 9mmTc-DMSA-V, to detect MTC recurrences in patient follow-up post-thyroidectomy.

Adult↗
PubMed1995

Comparison of labeled MIBG and somatostatin analogs in imaging neuroendocrine tumors.

In 10 patients with histologically proven neuroendocrine tumors (4 carcinoids, 4 pheochromocytomas, 1 medullary thyroid cancer and 1 Merkel tumor) the results of radiolabeled metaiodobenzylguanidine (MIBG) and somatostatin analogs were compared. A total of 24 tumor lesions was detected on standard imaging studies. MIBG scintigraphy correctly localized 12 (50%) of these lesions which were observed in 5 patients (4 with pheochromocytoma and 1 with carcinoid tumor). Scintigraphy using labeled somatostatin analogs correctly localized 21 (87%) lesions which occurred in 8 patients (4 with carcinoid, 2 with pheochromocytoma, 1 with medullary thyroid cancer and 1 with Merkel tumor). Concordant scintigraphic results were obtained in 1 patient with carcinoid and 2 with pheochromocytoma. In conclusion, although this series was limited, our results suggest that MIBG is more accurate than somatostatin analogs in imaging pheochromocytoma. Conversely, somatostatin analogs are more accurate than MIBG in detecting other neuroendocrine tumors such as carcinoids.

3-Iodobenzylguanidine↗
PubMed1994

Nasotracheal jet ventilation for rigid endoscopy.

Providing adequate ventilation and unencumbered access for manipulation of the airway or esophagus during rigid endoscopic procedures can be problematic. We describe a method of nasotracheal high-frequency jet ventilation that is ideally suited for many patients requiring rigid upper endoscopy.

Bronchoscopy↗
PubMed1994

Development of an intravenous membrane oxygenator: enhanced intravenous gas exchange through convective mixing of blood around hollow fiber membranes.

In vitro testing of a new prototype intravenous membrane oxygenator (IMO) is reported. The new IMO design consists of matted hollow fiber membranes arranged around a centrally positioned tripartite balloon. Short gas flow paths and consistent, reproducible fiber geometry after insertion of the device result in an augmented oxygen flux of up to 800% with balloon activation compared with the static mode (balloon off). Operation of the new IMO device with the balloon on versus the balloon off results in a 400% increase in carbon dioxide flux. Gas flow rates of up to 9.5 L/min through the 14-cm-long hollow fibers have been achieved with vacuum pressures of 250 mm Hg. Gas exchange efficiency for intravenous membrane oxygenators can be increased by emphasizing the following design features: short gas flow paths, consistent and reproducible fiber geometry, and most importantly, an active means of enhancing convective mixing of blood around the hollow fiber membranes.

Animals↗
PubMed1994

Non-Hodgkin's lymphoma in a patient with follicular thyroid cancer: the role of 99mTc-methoxy isobutyl isonitrile imaging.

In the post-surgical follow-up of a patient with follicular thyroid carcinoma, a palpable mass in the left supraclavicular region was highly indicative of metastatic disease. Technetium-99m methoxy isobutyl isonitrile (99mTc-MIBI) showed an increased but heterogeneous uptake within the lesion. Surprisingly, a different neoplastic disease was histologically demonstrated. Lymph node abnormalities due to non-Hodgkin's lymphoma rather than metastatic thyroid disease were demonstrated. In conclusion, non-Hodgkin's lymphoma may occur in patients with follicular thyroid carcinoma. This new lesion significantly concentrated 99mTc-MIBI. Thus, the results of 99mTc-MIBI imaging have to be carefully evaluated during the follow-up of patients with thyroid cancer.

Adenocarcinoma, Follicular↗
PubMed1994

Diagnostic evaluation of thyroid involvement by histiocytosis X.

UNLABELLED: We report the successful diagnosis of thyroid involvement by histiocytosis X due to accurate evaluation of nuclear medicine results. METHODS: A total thyroidectomy specimen from our patient was initially suggestive of medullary thyroid carcinoma. However, histologic reevaluation was performed on the basis of nuclear medicine findings which were incompatible with the original histologic diagnosis. RESULTS: Immunohistochemical and light microscopy studies were performed to obtain the correct diagnosis. Diffuse thyroid involvement by histiocytosis X was demonstrated. CONCLUSION: Thyroid scintigraphy was helpful in successfully diagnosing thyroid involvement by histiocytosis X. Because tracer uptake is related to increased cellularity and metabolism, none of these tracers reported here is specific for defining histiocytosis X.

3-Iodobenzylguanidine↗