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Biomedical subjects

A Samuel

Publications and source records attributed to A Samuel.

At least 19 recordsLinked to original sources
PubMed2001

Wound botulism in drug addicts in the United Kingdom.

Clostridium novyi has recently been identified as the causative organism responsible for the deaths of 35 heroin addicts who had injected themselves intramuscularly. We present two heroin addicts who developed C. botulinum infection following intramuscular or subcutaneous injection of heroin. Like C. novyi, this grows under anaerobic conditions and clinical presentation may be similar; however, descending motor or autonomic signs are invariably present in botulism. The prognosis is good if the diagnosis is made early and appropriate treatment commenced.

Adult↗
PubMed2000

[Whole-body oxygen consumption at different temperatures during cardiopulmonary bypass].

For evaluation of the adequacy of tissue perfusion during cardiopulmonary bypass (CPB), whole-body oxygen consumption rates at different body weights and temperatures are basic and important data. But few studies have analyzed the oxygen consumption estimated from real-time data during CPB in clinical situations. We analyzed retrospectively the oxygen consumption at different body weights (BW) during normothermia (VO2 37) and the oxygen consumption ratio at different body temperatures (BT; %VO2X; X = BT) from the CPB charts of 189 cases. From these charts, 877 data points for oxygen consumption during total CPB were calculated by Fick's law. By statistical analysis of these data, we derived the following formulae: VO2 37 (ml/kg/min) = 7.6481 x BW0.0679, R2 = 1.0 (BW < 8 kg) VO2 37 (ml/kg/min) = 32.394 x BW-0.625, R2 = 0.92 (BW > or = 8 kg) %VO2X (%) = 4 x 10(-5) x BT4.0777, R2 = 0.42. These formulae indicate that (1) the whole-body oxygen consumption during total CPB can be measured by subtracting the oxygen consumption associated with circulatory and respiratory processes from the oxygen consumption derived from the basal metabolism; and (2) although the change in oxygen consumption induced by hypothermia is variable depending on body weight, the rate of change shows no difference regardless of the patient's weight.

Body Weight↗
PubMed1999

The structure and function of a foot-and-mouth disease virus-oligosaccharide receptor complex.

Heparan sulfate has an important role in cell entry by foot-and-mouth disease virus (FMDV). We find that subtype O1 FMDV binds this glycosaminoglycan with a high affinity by immobilizing a specific highly abundant motif of sulfated sugars. The binding site is a shallow depression on the virion surface, located at the junction of the three major capsid proteins, VP1, VP2 and VP3. Two pre-formed sulfate-binding sites control receptor specificity. Residue 56 of VP3, an arginine in this virus, is critical to this recognition, forming a key component of both sites. This residue is a histidine in field isolates of the virus, switching to an arginine in adaptation to tissue culture, forming the high affinity heparan sulfate-binding site. We postulate that this site is a conserved feature of FMDVs, such that in the infected animal there is a biological advantage to low affinity, or more selective, interactions with glycosaminoglycan receptors.

Adaptation, Physiological↗
PubMed1999

[Surgical treatment of 2 cases of irradiation induced constrictive pericarditis].

A 72-years-old man underwent radiation therapy (62 Gy) for esophageal carcinoma. Twelve months later, symptoms of heart failure such as syncope, cough and hepatomegaly manifested. On catheter study, a dip and plateau pattern of right ventricular pressure curve was evident. Pericardiectomy without extracorporeal circulation was performed. Operative findings and pathological results were compatible with radiation-induced constrictive pericarditis. He recovered from the heart failure, and has been doing well 3 months after the surgery. A 54-years-old man underwent thymectomy for malignant thymoma. He underwent a radiation therapy (52 Gy) postoperatively. After 12 months from the irradiation, syncope and dyspnea manifested. On catheter study, a dip and plateau pattern of right ventricular pressure curve was observed. Pericardiectomy with extracorporeal circulation was performed. He recovered from the heart failure after pericardiectomy, however he died of radiation-induced pneumonitis 6 months later.

Aged↗
PubMed1999

Paget's disease of bone in Malta. A preliminary survey.

We present the results of a preliminary survey carried out on 46 patients with Paget's disease of bone in Malta, 40 of whom were seen at a general medical outpatient clinic and a further 6 at a primary health care centre over the first 6 months of 1997. Various aspects of the disease have been analysed: prevalence, age and sex distribution, familial aggregates, mode of presentation, complications, pattern of bone involvement, a semi-quantitative assay of disease activity as assessed by bone scintigraphy and serum alkaline phosphatase (SAP) levels, and the factors that influenced disease activity. The results have been compared to previous published surveys on Paget's disease in different countries.

Adult↗
PubMed1998

A novel serum free system for cloning human megakaryocytic progenitors (CFU-Meg). The role of thrombopoietin and other cytokines on bone marrow and cord blood CFU-Meg growth under serum free conditions.

Human megakaryocytic progenitors (CFU-Megs) are usually cloned in plasma clot cultures. Since the medium employed to prepare plasma clot contains animal or human serum, there exists a potential risk that CFU-Megs growing in vitro could be exposed to the serum derived megakaryopoietic inhibitors. To address this issue, we aimed to establish a relatively simple "serum free" cloning model for these progenitors. Accordingly, we found that if human bone marrow or cord blood CD34+ cells are plated in the methylcellulose medium containing serum substitute, and are stimulated with recombinant thrombopoietin (TpO), they exclusively form CFU-Meg colonies. Subsequently these colonies can be easily scored with an inverted microscope based only on their morphological criteria. We found that the cloning efficiency of CFU-Megs was higher in our serum free cloning system than in the traditional plasma clot cultures. Since the model proposed in this paper is relatively simple, and moreover does not require time consuming immunostaining to identify CFU-Meg colonies, it should be widely recommended for studying in vitro human megakaryopoiesis. We also found, that under serum free conditions TpO is crucial for CFU-Meg formation. In absence of TpO, neither gp 130 activating cytokines (IL-6, IL-11, LIF, CNTF) nor the other hematopoietic growth factors or cytokines (KL, IL-3, GM-CSF, EpO) were able, when added alone, to stimulate the growth of human CFU-Meg colonies. Finally, we report also that cord blood CD34+ cells are enriched in megakaryocytic progenitors, and moreover, CFU-Megs from cord blood possess a higher proliferative capacity than CFU-Megs isolated from normal adult bone marrow.

Antigens, CD34↗
PubMed1998

[Fenestration of diaphragm for management of persistent postoperative pleural effusion: clinical experience and experiment in rabbits].

UNLABELLED: The management of persistent postoperative pleural effusion is still considered difficult. We report here our experience with such a case, successfully managed with fenestration of the diaphragm-the first of it's kind. Clinical Experience: A two-year-old boy with double outlet right ventricle, underwent right heart bypass procedure. Due to low output and high venous pressure, he was on ventilator until the 26th postoperative day. The pericardial and right pleural effusion persisted till the 60th postoperative day. Right phrenic nerve palsy and atelectasis of right lower lobe were suspected to contribute to it. We performed a plication of the right diaphragm and fenestration of the pericardium and right diaphragm. A T-shaped incision was made on the right diaphragm and the edges were trimmed and strengthened with non-absorbable suture into a circular shaped defect of 1.5 cm diameter. The defect was closed with a Dacron mesh allowing passage of fluid across. Pleural effusion decreased immediately and he was discharged a month after the procedure. Experimental Study: The above procedure was experimented in rabbits in whom a contrast medium injected into the pleural cavity could easily drain into the peritoneum through the fenestation, proved by fluoroscopy. CONCLUSION: Fenestration of the diaphragm is an effective procedure to manage persistent pleural effusion.

Animals↗
PubMed1996

Pretargeted immunoscintigraphy in patients with medullary thyroid carcinoma.

To evaluate the use of pretargeted immunoscintigraphy (ISG) in the diagnosis and follow-up of patients with medullary thyroid carcinoma (MTC), we studied 25 patients with histologically proven disease; ISG was repeated after surgery in two patients. The antibody, either an anticarcinoembryonic antigen (CEA) or an antichromogranin A (CgA) biotinylated monoclonal antibody (MAb) or a cocktail of the two biotinylated MAbs was first injected. After 24 h, avidin was administrated i.v., followed by 111In-labelled biotin 24 h later. Fifty-two lesions were visualised. Six primary tumours, diagnosed by increased calcitonin levels, were all correctly diagnosed; 47 recurrences, also suspected by blood tumour markers, were detected and confirmed by cytology or histology. In one case, single photon emission tomography allowed the detection of small lymph nodes with a diameter of 4-7 mm. These lesions, not judged neoplastic by ultrasound, were confirmed to be neoplastic by fine needle aspiration. Pretargeted ISG correctly localises primary tumours and recurrences in MTC patients, when the only marker of relapse is serum elevation of calcitonin. With this three-step pretargeting method, cocktails of potentially useful MAbs can be used, avoiding false-negative studies that may occur when CEA or CgA are not expressed.

Adolescent↗
PubMed1996

Detection of prosthetic vascular graft infection using avidin/indium-111-biotin scintigraphy.

UNLABELLED: Prosthetic vascular graft infection, though rare, carries high morbidity and mortality rates; therefore, timely diagnosis is important. Patients, however, often present with vague symptoms, and radiological investigations are frequently inconclusive. These factors may lead to prolonged periods of observation and hospitalization, with the resultant increase in costs and complication rates, before reaching a final diagnosis. This prospective study evaluates the use of nonspecific avidin/111In-biotin imaging in diagnosing prosthetic vascular graft infection. METHODS: Twenty-five patients with a total of 29 grafts were investigated. Eighteen patients (19 grafts) had low probability of disease, whereas the remaining 7 patients (10 grafts) warranted surgical exploration based on clinical, laboratory or radiological evidence. Avidin was first injected intravenously and then followed 24 hr later by administration of 111In-biotin. Whole-body images were obtained 10 min and 2 hr postinjection of 111In-labeled biotin. SPECT imaging was performed 1 hr postinjection. Increased uptake along part or the whole length of the graft was considered evidence of graft infection. RESULTS: Avidin/111In-biotin scintigraphy correctly identified all infected grafts, as confirmed by culturing surgical specimens. In contrast, infection was correctly excluded in all but one of the grafts, and long-term follow-up was used to assess the presence of infection in patients who did not undergo surgical intervention. CONCLUSION: Avidin/111In-biotin scintigraphy is a simple and accurate imaging method for the routine diagnosis of vascular graft infection, and it may have a role in identifying the disease process in its initial stages, thus improving prognosis.

Aged↗
PubMed1995

Plasma sialic acid in animal models of diabetes mellitus: evidence for modulation of sialic acid concentrations by insulin deficiency.

An elevated circulating sialic acid concentration is a risk factor for cardiovascular disease. Serum sialic acid levels are elevated in NIDDM but not in uncomplicated IDDM. To study why sialic acid is increased in some types of diabetes, we assayed plasma sialic acid in various animal models of diabetes: obese (ob/ob) mice, before and after streptozotocin treatment, neonatal streptozotocin-treated (nSTZ) rats, and diabetic BB rats during and after insulin treatment. In obese mice, which exhibit moderate hyperglycemia and marked hyperinsulinemia, plasma sialic acid was decreased by 45% (fed) and 42% (fasted), compared to lean controls. Fasting reduced plasma glucose and insulin but increased sialic acid in the obese and lean mice. There was a negative correlation (r = -0.84, P < 0.001) between log plasma insulin and sialic acid in the lean and obese mice. The plasma sialic acid:globulin ratio was reduced by 35% in obese mice vs. lean controls, indicating that there may be altered sialylation of glycoproteins in obese mice. Streptozotocin treatment of obese and lean mice reduced plasma insulin but increased sialic acid. In nSTZ rats, hyperglycemia was associated with mild hypoinsulinemia, but not significantly different from control animals, and sialic acid was not altered. In diabetic BB rats, plasma glucose rose from a mean of 4.9 to 23.5 mM 48 hr after insulin withdrawal but sialic acid did not change. We conclude that an elevated plasma sialic acid level is associated with marked insulin deficiency, rather than hyperglycemia per se. The magnitude and speed of this change in sialic acid varies between species.

Animals↗
PubMed1995

Avidin and 111In-labelled biotin scan: a new radioisotopic method for localising vascular graft infection.

OBJECTIVES: To evaluate a new imaging technique, for diagnosis of prosthetic vascular graft infection. Avidin is a protein which accumulates nonspecifically at sites of inflammation or infection. Due to its extremely low dissociation constant with biotin sites of infection can be imaged, using avidin as a pre-target, followed by injection of 111In-labelled biotin. This technique is much simpler than the common scintigraphic methods which employ labelling of blood components and its target-to-background ratio is greater than the methods employing radiolabelled proteins. DESIGN: Prospective clinical study. SETTING: A single department of vascular surgery and one of nuclear medicine of a Northern Italian hospital. MATERIALS: Between May 1993 and May 1994, 31 grafts in 26 patients were studied; the series included 23 men and three women with a mean age of 65.5 years (range 54-76 years). The prosthetic graft (Dacron -16, ePTFE -15) were: aortoaortic 5, aortobifemoral 15, aortoiliac 1, and femoropopliteal 10. Sixteen patients were suspected of having a vascular graft infection (Group A), the other 10 patients served as controls (Group B). 20 mg of Avidin were injected iv, followed 24 h later by i.v. injection of 500 micrograms of Biotin labelled with 74 MBq of 111In. CHIEF OUTCOME MEASURES: Whole-body imaging was performed at 10 min and 2 h post-injection, along with SPECT imaging when indicated. Scan results were correlated with the traditional imaging modalities and the clinical outcome of the patients. MAIN RESULTS: In Group A: two patients (three grafts) were excluded from the study, there were six true-positives, one false-positive and 11 true-negatives. Results in Group B: 10 true-negatives. The overall sensitivity was 100%, the specificity 95%, the accuracy 96%, the positive predictive value 86% and the negative predictive value 100%. CONCLUSIONS: These data suggest that Avidin/111In-labelled Biotin scintigraphy is a useful non invasive diagnostic method for early diagnosis of suspected prosthetic vascular graft infection.

Aged↗
PubMed1993

Three-step tumor pre-targeting in lung cancer immunoscintigraphy.

Radiolabelled MoAbs have been used in both the diagnosis and the treatment of a variety of tumors. Recently, a three-step tumor pre-targeting strategy has been proposed to overcome one of the major limiting factors in radioimmunodetection: the low tumor-to-background ratio. We evaluated this pre-targeting protocol in 10 patients diagnosed as having pulmonary carcinoma. One milligram of biotinylated anti-CEA MoAb (FO23C5) was administered i.v. (1st step); 24 hours later 5 mg of avidin was injected i.v. (2nd step) followed by 100-500 ng of 111In-biotin (5 mCi) the day after (3rd step). Imaging was performed using single photon emission tomography (SPET). No toxicity and no adverse reactions were observed. Tumor was detected in 8 out of 10 patients. Mediastinal metastases were also localised in 2 out of 3 patients, and adrenal gland recurrency in 1 out of 2 patients. The tumor/background (normal lung), heart, liver and spine ratios were respectively 2.0, 1.0, 1.3 and 4.1 at 90 minutes post-injection. These preliminary data show that the three-step pretargeting method is safe and allows SPECT tumor localization soon after the injection of the radiolabel. In the future, the use of MoAbs with higher specificity could result in improved tumor-targeting, and in the possibility of lung cancer radioimmunotherapy.

Aged↗
PubMed1993

Contact thermography in the diagnosis of childhood migraine.

The objective of our prospective study was to assess the role of contact thermography in children with migraine. Contact thermograms were done in 54 children aged 4.2-16.5 years (median 10.5 years), who were seen for headache and on 10 age-matched controls, between July and December 1991. Thermograms were interpreted as definitely normal, equivocally normal, equivocally abnormal, and definitely abnormal by a radiologist who was blinded to clinical information. Forty-eight children had the test between headaches; of these, four out of 26 patients (15%) who had migraine without aura and 3 out of 14 children (21%) who had migraine with aura had definitely abnormal thermograms. Nine out of 10 normal controls had definitely normal thermograms. The sensitivity of contact thermography in the diagnosis of childhood migraine, when done between headaches, was low in our study.

Adolescent↗
PubMed1990

Exploratory project for development of nursing outcome criteria in long term care.

This exploratory project in developing outcome criteria for long term care was conducted with the view that the individual professional nursing practitioner has a unique, valuable contribution to make to the overall nursing quality assurance effort. Twenty-seven nurses volunteered to design and conduct individual systematic nursing diagnosis/intervention/outcome measurement projects. They were employees of five long term care facilities in New York state. Their contribution to this project was an embodiment of their professional judgement and practice with 107 selected clients under their care. They were prepared for participation through instruction repeated in all five facilities. The North American Nursing Diagnosis Association's Taxonomy of Nursing Diagnoses was used in the instruction, by the practitioners in their practice and data collection, and in the data analysis. Data analysis also included use of Campbell's nursing intervention category scheme. This work demonstrated that professional nurses are able to specify appropriate outcome criteria and to measure these outcomes of their planned nursing interventions. Eighty-seven percent of the expected outcomes were achieved as anticipated or in the anticipated direction. Results provided many leads for future study of nursing diagnosis/intervention/outcome measurement among residents of long term care institutions.

Humans↗
PubMed1989

Antibiotic sensitivity of enterobacteriaceae by disc diffusion and rapid fermentation sensitivity test methods.

A total of 400 strains of Gram negative bacilli were examined both by conventional disc diffusion (DD) and by rapid fermentation sensitivity test (RFST) methods. Various strains which were examined included Esch. coli Kleb. aerogenes, Kleb. pneumoniae, Prot. vulgaris, Prot. mirabilis, Prot. morgani, Prot. rittgeri and Providencia. The antibiotics used were streptomycin, chloramphenicol, kanamycin, gentamycin and ampicillin. The correlation between the two methods was found to vary from 75 to 98 per cent. By RFST method the results are obtained within six hours. The limitations of this method are (i) it cannot be used for Pseudomonas aeruginosa as it does not ferment glucose, (ii) it cannot be used for antibiotics active only at acidic pH like tetracycline and (iii) partial or intermediate sensitivity cannot be tested by this method. On the other hand, it is a simple, inexpensive, rapid and reliable method feasible in small laboratories also. The results are not affected by the size of inoculum or quality of medium (agar) used. Thus, it is very helpful especially when immediate antibiotic sensitivity is required.

Diffusion↗