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Biomedical subjects

M Frank

Publications and source records attributed to M Frank.

At least 91 records · Page 5Linked to original sources
PubMed1997

[Reactive thymus dysplasia following therapy for ACTH-producing tumors].

UNLABELLED: Surgical or conservative treatment of ACTH-producing tumors results in acute drop of the previously excessively high cortisol levels. The following associated pathophysiological changes also occur in the organism's recovery from stress, such as trauma, operation or chemotherapy of tumors. Both cases result in a regeneration of the immune system, which might even be exalted. The corresponding radiographic feature is the "rebound" enlargement of the thymus occurring about six months after remission of hypercortisolism. Histological examination reveals benign thymus hyperplasia. Especially in cases of still unknown primary tumor the appearance of this anterior mediastinal mass can lead to misdiagnosis. We present the cases of two patients with diffuse thymic hyperplasia following surgical and medical correction of hypercortisolism. One patient suffered from classic Cushing's disease responding to transsphenoidal resection of an ACTH-secreting pituitary microadenoma. Six months later CT of the chest incidentally demonstrated an anterior mediastinal mass known as thymic hyperplasia. The second patient presented with an ectopic, still unkown source of ACTH-production. Six months after medical correction of hypercortisolism CT of the thorax showed an enlargement of the anterior mediastinum. Thymectomy was performed in order to exclude thymus carcinoid. Histological examination revealed benign thymus hyperplasia with negative immunostaining. CONCLUSION: Radiologists and clinicians should be familiar with the pathophysiological changes resulting from precipitously dropping cortisol levels in order to prevent diagnostic errors and unnecessary operations.

Adrenocortical Hyperfunction↗
PubMed1997

Modified ultrafiltration after cardiopulmonary bypass in pediatric cardiac surgery.

BACKGROUND: Cardiopulmonary bypass in children results in considerable water retention, especially in neonates and small infants. Dilution of plasma proteins increases water loss into the extravascular compartments. Excessive total body water may prolong ventilatory support and may contribute to a prolongation of intensive care convalescence. After discontinuation of cardiopulmonary bypass, modified ultrafiltration can be used to withdraw plasma water from the total circulating volume. METHODS: This retrospective study included 198 pediatric patients who underwent cardiac operations in the period from September 1991 to November 1994. Two groups were compared: 99 patients without ultrafiltration and 99 patients receiving modified ultrafiltration. The following indices were analyzed: cardiopulmonary bypass prime volume, transfused blood volume during and after the operation, postoperative chest drain loss, and hemoglobin and hematocrit levels before, during, and after the procedure. RESULTS: Modified ultrafiltration resulted in a significant increase in hemoglobin and hematocrit levels and a significantly lower amount of transfused blood. Mean postoperative chest drain loss was significantly less in the patients who underwent modified ultrafiltration. CONCLUSIONS: Modified ultrafiltration decreases blood transfusion requirements and chest drain loss after pediatric cardiac surgical procedures.

Blood Transfusion↗
PubMed1997

Chromosomal localization of the myelin-associated oligodendrocytic basic protein and expression in the genetically linked neurological mouse mutants ducky and tippy.

The alternatively spliced cDNAs encoding the myelin-associated/oligodendrocytic basic proteins (MOBPs) have recently been identified in rat. The Mobp gene maps to the distal part of mouse chromosome 9 at a region syntenic with the human chromosome 3p22-p21.3. Two nonallelic mouse mutants, tippy and ducky, with severe neurological phenotypes map to the vicinity of the Mobp locus. We therefore tested whether MOBP malfunction could explain the tippy and ducky defects. In tippy mutant animals, MOBP expression and that of other myelin markers were indistinguishable from wild type. The ultrastructure of tippy myelin was shown to be normal. Ducky animals showed a slight reduction of the brain size, most evident in the spinal cord, but normal progress of myelination. Both MOBP and myelin basic protein expression were lowered only regionally in the CNS, but were mostly normal in the anterior parts of the brain. Ultrastructurally, ducky myelin appeared normal. MOBP transcript sizes and the molecular weights of the encoded proteins were shown to be normal in both mutants. Finally, the nucleotide sequence of the abundant MOBP-81 cDNA was determined and compared with tippy and ducky MOBP-81. Wild-type mouse MOBP-81 protein was 99% identical to the rat homologue, and tippy and ducky MOBP-81 were identical to the wild-type sequence. Our results suggest that alterations in the Mobp gene are not the cause for the severe neurological phenotypes of ducky and tippy mice.

Alternative Splicing↗
PubMed1997

Haem precursors and porphobilinogen deaminase in erythrocytes and lymphocytes of patients with acute intermittent porphyria.

Patients with AIP can be subdivided into three different groups concerning their PBGD activity in erythrocytes: The first of which has lowered, the second overlapping and the third normal PBGD activity. Out of 385 AIP patients 87% had lowered, 8% had overlapping and 5% had normal PBGD activity. Gene carriers of AIP having slight, moderate or high metabolic aberrations of excretion parameters are recognized by analysis of urinary haem precursors and faecal porphyrins. The haem precursor excretion of the groups with lowered, overlapping and normal PBGD activity in erythrocytes compared to each other is not significantly different but differs significantly (p < 0.001) from the normal values. One individual suffering from AIP was detected in a family with normal PBGD. Lymphocytes can be stored in liquid nitrogen for 3 months without loss of PBGD activity. Specific PBGD activity in lymphocytes is 5% from specific PBGD activity in erythrocytes. In AIP patients with lowered specific PBGD activity in erythrocytes specific PBGD activity is lowered to the same extent in their lymphocytes.

Adult↗
PubMed1996

Theileria annulata: in vitro cultivation of schizont-infected bovine lymphocytes.

Experimental parameters of optimization of the in vitro growth conditions for Theileria annulata schizont-infected bovine lymphoid cells are presented. Of the nine different media tested in the course of 14 successive passages, Leibovitz L-15 (L-15) and a combination of McCoy and Leibovitz L-15 (ML) were preferable to McCoy, Dulbecco (DMEM), RPMI 1640 or Eagles's minimum essential medium (MEM) based on either Hank's or Earle's salts. The lowest multiplication rate was obtained with M-199 medium based on Hank's or Earle's salts. The highest yield of cells was obtained when L-15 was supplemented with 20% newborn bovine serum, while lowering the serum concentration by half resulted in a 25% decrease in cell yield. There was no effect on multiplication rate observed during ten passages when 2-mercaptoethanol and a mixture of oxaloacetate, sodium pyruvate and insulin were added to the growth medium. On substitution of conditioned medium for 20 or 50% of the growth medium, the yield of cells decreased by 12 or 20%, respectively, a factor which might be considered in calculations of the cost of anti-T. annulata vaccine production. When cells were grown in stationary cultures in Roux bottles for 7 days without change of medium, the highest yield resulted from seeding at 10(7) cells per vessel (100 ml) in L-15 supplemented with 20% serum. In Roller bottles, with the same type and volume of medium and cultivation for 7 days without medium change, best yield resulted from seeding with the highest inoculum size of 4 x 10(7) cells per vessel.

Animals↗
PubMed1996

[Diagnostic localization of insulinoma. Experiences with 25 patients with solitary tumors].

OBJECTIVE: The most effective way to localize the mostly small ( < 2 cm), benign and solitary insulinomas is still under discussion. Especially the evaluation of the different preoperative localization methods is not clarified. The aim of our study was to support the ongoing discussion in that matter. PATIENTS AND METHODS: In total 25 patients have been included in our study since 1987. All showed sporadic insulinomas and underwent surgery. The following preoperative localization methods had been used: ultrasonography (US): 25 patients, computed tomography (CT): 23 patients, somatostatin receptor scintigraphy (SRS): four patients since 1990, angiography: six patients, endosonography (ES): five patients since 1995, selective portal venous sampling (PVS): two patients, magnetic resonance imaging (MRI): four patients since 1993. All 25 patients underwent a bidigital palpation in combination with intraoperative ultrasonography (IOUS). Four of the 25 patients were reoperated and had a prior unsuccessful operation elsewhere. RESULTS: Preoperatively 19 of 25 insulinomas were localized (76%). The following sensitivity rates had been found: ultrasonography: 56%, computed tomography: 43%, endosonography: 100%, angiography: 66%, magnetic resonance imaging: 25%, selective portal venous sampling: 100%, somatostatin receptor scintigraphy: 0%. All 25 insulinomas were detected during operation, 100% by palpation in combination with intraoperative ultrasonography and 92% by palpation on its own. CONCLUSION: After an insulinoma is biochemically proven and after exclusion of a malignant metastasizing tumor by ultrasonography, all patients should be operated on. Intraoperative ultrasonography should be performed in any case. As other preoperative localization methods did not prove a convincing cost-utility-relation, one should not consider the usage of these methods before the initial operations. Before re-operations one should consider the use of costly pre-operative methods to localize insulinomas. Here endosonography and selective portal venous sampling are recommended as the first procedures of choice.

Adolescent↗
PubMed1996

A convenient new pathway for stereospecific epimerization of monosaccharide moieties in disaccharides.

The disaccharides benzyl 4,6-O-benzylidene-2-O-alpha-D-mannopyranosyl-beta- D-glucopyranoside (2), 6-O-beta-D-galactopyranosyl-1,2:3,4-di-O-isopropylidene-alpha-D- galactopyranose (4), and phenyl 4-O-beta-D-galactopyranosyl-1-thio-beta-D-glucopyranoside (7) were selectively acetalated with chloral-dicyclohexylcarbodiimide in a nonclassical pathway. During acetalation, the D-mannopyranosyl moiety of the disaccharide 2 and the unprotected beta-D-galactopyranosyl moieties of 4 and 7 were epimerized at their 3-positions, generating D-altro- and D-gulo-pyranosyl moieties, respectively.

Carbohydrate Conformation↗
PubMed1996

Cellular reactions at the lesion site after crushing of the rat optic nerve.

Rat optic nerves were subjected to crush injury to study the local tissue reactions leading to wound healing and tissue repair. We used antibodies against glial fibrillary acidic protein (GFAP), vimentin, the S1OO protein (S1OOP), lysozyme, and ED1 as markers for astroglial cells and microglia/macrophages at the light and electron microscopic level during the 3 weeks following the crush. The crush injury produced a vast area of tissue damage including the disruption of the blood-brain barrier (BBB). In the first days after crushing, astrocytes were absent from the lesion site. S1OOP-positive astrocytes reappeared in the lesion center as early as 6 days after crushing. These astrocytes reestablished former topological structures such as perivascular and subpial glia limitans. At the edges of the lesion site reactive astrocytes enclosed and embedded axonal and myelin debris. Preceding the astroglial repopulation, a massive infiltration of microglia/macrophages (phagocytes) into the lesion center took place. ED1-positive/lysozyme- positive cells of round shape were seen in the lesion center at 2 days after crushing, and their number peaked around 1 week after crushing. They efficiently cleared the debris from the lesion site and mostly disappeared after 3 weeks. With immuno-electron microscopy we found the ED1 antigen related to the membranes of phagosomes. The microglia/macrophages observed in the nerve segments distal of the lesion (Wallerian degeneration site) were different from those in the lesion center: 1) they appeared later, about 6 days after crushing; 2) they were ED1 positive, but lysozyme negative and showed a branched morphology; and 3) they persisted in the distal nerve segment but showed little phagocytosis. We suggest that these cells are mostly activated microglia.

Animals↗
PubMed1996

Assessment of analgesia in man: tramadol controlled release formula vs. tramadol standard formulation.

OBJECTIVE: The present study tested analgesia produced by a new controlled release formulation of tramadol. The investigation employed an experimental pain model based on chemo-somatosensory event-related potentials (CSSERP) in response to painful chemical stimuli applied to the nasal mucosa. STUDY: Twenty healthy volunteers participated in the experiments, which followed a controlled, randomised, double-blind, 3-way cross-over design. Each of the three medications (tramadol 100 mg [T100], tramadol controlled release 100 mg [TCR100] and tramadol controlled release 150 mg [TCR150]) was administered orally to fasting subjects. There was at least a 6 day washout period between tests. Each experiment was divided into five sessions, which took place before and 2, 4, 6, and 12 h after drug administration. In addition to the assessment of CSSERP, subjects rated the intensity of both the tonic and phasic painful stimuli. Nonspecific drug effects were also monitored by means of frequency analysis of the spontaneous EEG, ratings of adverse effects, and the subjects' performance in a tracking task. RESULTS: The significant reduction of amplitude N1 at central recording positions indicated that TCR 150 was the most effective analgesic 12 h after administration. Both 6 and 12 h after administration TCR 100 was more effective in terms of analgesia compared to T100. In addition, TCR100 appeared to produce fewer adverse effects than the standard formulation of tramadol. CONCLUSIONS: The controlled release formulation can be expected to become a valuable tool in peroral therapeutic regimens for chronic pain.

Adult↗
PubMed1996

Gastrointestinal endocrine tumours: medical management.

With the introduction of longer-acting somatostatin analogues symptomatic relief is easy to achieve in patients with functionally active endocrine tumours and will be further facilitated by still longer-acting formulations. The consequences of gastric acid hypersecretion in patients with Zollinger-Ellison syndrome can be prevented by all proton-pump inhibitors currently on the market. Despite the various antiproliferative strategies that have been offered to patients with metastatic disease, available data are controversial and, more importantly, are supported by few prospective and controlled studies. Most experts agree that surgery with curative extirpation of the primary in the absence of metastases and tumour debulking in metastatic disease should be intended wherever possible. Controversy concerns residual disease. According to our view, any further antiproliferative strategy should consider the growth characteristics and biology of a given tumour (Figure 4). In the case of rapid progression, chemotherapy should be offered if tumours originate from the pancreas or reveal an undifferentiated histology. In contrast, chemotherapy should not be offered to patients with well-differentiated non-functional or functional tumours (carcinoid syndrome) arising from the intestine. The same applies for patients with tumours with no or only slow growth within an given observation period of 3-12 months. These patients should be treated only symptomatically. Patients with tumours of slow progression might favourably respond to long-acting somatostatin analogues. We start with octreotide and offer patients not responding to octreotide monotherapy additional IFN alpha. If further tumour progression takes place, hepatic artery embolization is the next step (Figure 5) followed by chemotherapy, the latter in patients with tumours of pancreatic origin only. This strategy recognizes the severity of side-effects of the different therapeutic modalities and starts with octreotide because of its very few side-effects. Other groups start with chemoembolization followed by octreotide, alpha-interferon or its combinations (Ahlman et al, 1996). Ongoing studies will, it is hoped, answer the question of the ideal sequence of therapeutic strategies. Every available patient with metastasised gastrointestinal endocrine tumours should be included in one of the ongoing European multicentre trials.

Antineoplastic Agents↗
PubMed1996

Control of growth in neuroendocrine gastro-enteropancreatic tumours.

This paper reviews data on the effect of pharmacological anti-tumour agents on tumour growth in patients with malignant gastro-enteropancreatic (GEP) tumours. Agents include long-acting somatostatin analogues, interferon-alpha, a combination of both, chemotherapy, and chemo-embolisation. Characteristics of tumours are considered which should be taken into account in the management of patients with metastatic endocrine GEP tumours, including growth rate. Tumour type should be matched to the anti-proliferative strategy.

Animals↗
PubMed1996

[Reversible esophageal dysfunction as a side effect of levodopa].

We are reporting the case of a 94-year-old male patient with a 10-year history of Parkinson's disease, who was admitted to our hospital with acute obstruction of esophageal passage. Esophageal obstruction was refractory to endoscopic intervention. However, discontinuation of the pre-existing levodopa medication led to its resolution within hours. While dysphagia is commonly encountered in patients with Parkinson's disease, the observed succession of drug discontinuation and resolution of obstruction in this case suggests an as yet rarely described side effect of levodopa. This potential side effect should be included in the differential diagnosis of dysphagia in Parkinson's disease, especially in the case of older patients, who may exhibit an increased rate of intestinal absorption of levodopa.

Aged↗
PubMed1995

Differentiating between Besnoitia besnoiti from cattle and Sarcocystis hoarensis from rodents.

To provide a biological basis for studies designed to establish the mode of transmission of the veterinary pathogen Besnoitia besnoiti, we compared salient features of this pathogen in cattle with those of Sarcocystis hoarensis in rodents. The cysts and cystozoites of these organisms can readily be distinguished morphologically. In contrast to S. hoarensis, which is well adapted to rodents, B. besnoiti fails to mature in jirds or mice and generally is lethal in jirds. Serological reagents discriminately detect these pathogens. B. besnoiti, therefore, can unambiguously be differentiated from S. hoarensis either by morphological or serological methods or on the basis of experimental comparisons of virulence in laboratory rodents.

Animals↗