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Biomedical subjects

P Frey

Publications and source records attributed to P Frey.

At least 91 records · Page 5Linked to original sources
PubMed1987

Immunohistochemical evidence for a spinothalamic pathway co-containing cholecystokinin- and galanin-like immunoreactivities in the rat.

Using indirect immunofluorescence technique combined with retrograde tracing as well as surgical lesions, a system of spinothalamic neurons containing both galanin- and cholecystokinin-like immunoreactivity has been defined. The cell bodies are located in the lumbar segments L1-L5 with a preferential localization dorsal to the central canal at rostral levels and lateral to the canal at caudal levels. The cells project via the ventral part of the lateral funiculus to the most ventral and posterior parts of thalamus. Here a distinct, varicose terminal network was seen extending caudally from an area lateral to the medial lemniscus, running medially over the medial lemniscus, traversing the parafascicular nucleus and running dorsal to the fasciculus retroflexus into the periventricular gray matter. Transection of various parts of the spinal cord as well as retrograde tracing experiments indicate that the spinothalamic galanin cholecystokinin system represents a crossed pathway. The present results demonstrate that a spinothalamic system can be characterized by its content of galanin- and cholecystokinin-like peptides, two putative messenger molecules. It is only a minor component of the total spinothalamic projection.

Animals↗
PubMed1987

High density avalanche chamber (HIDAC) positron camera.

A prototype positron camera has been constructed consisting of two high density avalanche chamber (HIDAC) detectors operated in coincidence with a resolving time (2 tau) of 40 nsec. The detectors are multiwire chambers, with specially constructed lead converters added to improve the photon detection efficiency at 511 keV. The current HIDAC detectors have a singles efficiency of approximately 12%, a sensitive area of 31 X 31 cm and an intrinsic spatial resolution of less than 2 mm full width at half maximum (FWHM). During data acquisition, the detectors are rotated around the patient in order to collect a complete angular data set. A three-dimensional image of the positron distribution is reconstructed from a single scan by weighted backprojection of the data into a matrix of either 64 X 64 X 64 or 128 X 128 X 16 voxels. The camera point response function is deconvolved by frequency-space filtering. Corrections are made during backprojection both for photon attenuation and for spatial variations in point source sensitivity. The reconstructed image is further corrected for contributions from accidental and scattered coincidences and displayed as a sequence of two-dimensional transverse, sagittal, or coronal sections. In addition, three-dimensional display is available using shaded graphics techniques. The prototype camera is currently undergoing clinical evaluation.

Bone Neoplasms↗
PubMed1986

Does cholecystokinin-like immunoreactivity in rat primary sensory neurons represent calcitonin gene-related peptide?

Using immunohistochemistry, calcitonin gene-related peptide (CGRP)- and cholecystokinin (CCK)-like immunoreactivity (LI) were found in many of the same spinal and trigeminal ganglion cells and motoneurons in the spinal cord and hypoglossal nucleus, as well as in fibers with an overlapping distribution in the spinal cord (dorsal horn, bundle ventral to the central canal) and in the spinal trigeminal nucleus. CCK-LI in all these structures disappeared after preadsorption of CCK antisera with CGRP at 10(-4) M and almost completely at 10(-5) M. CCK peptide in concentrations up to 10(-4) M, on the other hand, did not influence CGRP staining. The present findings raise the possibility that some CCK-LI in primary sensory neurons in rat may represent CGRP or a similar peptide.

Animals↗
PubMed1986

Tomographic imaging of the human thyroid using 124I.

After receiving between 100 and 300 mu Ci of the positron-emitting radioisotope 124I (half-life, 4.2 days), 64 patients with a variety of thyroid disorders were imaged with a high resolution positron camera. A 3-dimensional image of the distribution of radioiodine uptake within the thyroid was obtained from a single 10- to 15-min scan. This image may be viewed as a sequence of 2-mm thick transverse, sagittal, or frontal sections or as a 3-dimensional shaded surface. The functional volume of the thyroid may be estimated by counting the volume elements (voxels) inside the thyroid surface. The precision of the estimate varied from 6-15%, depending on the size and clinical status of the thyroid. The volume estimation procedure was validated with phantoms and with the thyroids of patients who subsequently underwent partial thyroidectomy. This 3-dimensional imaging technique may be useful for diagnosis and management of thyroid diseases.

Adenoma↗
PubMed1985

In vivo imaging of the human thyroid with a positron camera using 124I.

A high-density avalanche chamber (HIDAC) positron camera was used for tomographic imaging of the human thyroid in vivo. Images were made 7 and 24 h after the oral administration of the positron-emitting radionuclide, sodium iodide 124I (with activities varying between 0.3 and 1 mCi), to patients scheduled for either partial thyroidectomy or radioiodine treatment. The results of thyroid imaging performed on 38 patients and their clinical relevance are discussed; as an illustration, three typical cases are presented. In Graves' disease, it was found that, whereas standard 131I and 124I scintigrams showed a diffuse goitre, positron images indicated a marked heterogeneity of the activity distribution, with "cold" areas in 8 out of the 11 cases studied. In conventional scintigrams, multinodular goitre showed a non-uniform radioiodine distribution, while positron images revealed considerable regional differences of activity uptake, with hot and cold areas in all of the 13 cases studied. As a consequence of the high spatial resolution of the camera [2.5 mm full width at half maximum (FWHM)], the functional volume of the thyroid may be estimated from 2 mm-thick transverse tomographic sections to within about 13%. This estimate may be compared with the measured volume after partial thyroidectomy, and in a follow-up scan, a further estimate can be made of the residual thyroid tissue remaining within the patient's body. In the case of radioiodine treatment in Graves' disease and multinodular goitre, the appropriate therapeutic dose of 131I can calculated according to the functional volume of the thyroid estimated from 124I tomographic images.

Adult↗
PubMed1985

Tomographic imaging of the human thyroid with a positron camera before and after partial thyroidectomy.

A high-density avalanche chamber positron camera was used for tomographic imaging of the human thyroid before and after partial thyroidectomy. Images were made between 6 and 24 h after oral administration of the positron-emitting radionuclide, Na-124I with activities varying between 0.1 and 0.3 mCi before the surgical intervention and with activities between 0.03 and 0.05 mCi following partial thyroidectomy. The results of thyroid imaging performed on 50 patients and their surgical relevance are discussed; as an illustration, one typical case is presented. As a consequence of the high spatial resolution of the camera (2.5 mm full width at half maximum), the functional volume of the thyroid may be estimated from the transaxial tomographic sections before and following partial thyroidectomy, correct to about 10%. The thyroid surface, defined by the contours from each transaxial section, may be displayed using three-dimensional shaded-graphics techniques. This new imaging technique makes possible a fully three-dimensional description of the thyroid in vivo and contributes significantly to the surgical follow-up.

Goiter, Nodular↗
PubMed1983

Cholecystokinin octapeptide levels in rat brain are changed after subchronic neuroleptic treatment.

Cholecystokinin octapeptide sulfate (CCK-8-S), nonsulfated cholecystokinin octapeptide (CCK-8-NS) and cholecystokinin tetrapeptide (CCK-4) levels in rat brain were measured by a combination of high pressure liquid chromatography (HPLC) and radioimmunoassay (RIA) after acute and subchronic treatment of the animals with haloperidol. CCK levels did not change after acute treatment. However, CCK-8-S concentrations were increased in the striatum and the mesolimbic system after two weeks of haloperidol treatment and remained increased after four weeks of haloperidol treatment. A transient decrease in CCK-8-S concentrations was observed in the cortex. Treatment with chlorpromazine or clozapine gave similar results. No changes in CCK-8-NS or CCK-4 concentrations were seen in any of the experiments.

Animals↗
PubMed1982

[Continuous monitoring of blood gases in adults].

Single blood gas analysis offers only a momentary value, whereas with continuous monitoring of blood gases their development can be followed very closely. Cutaneous pO2 monitoring has not proved successful in adults, since the measured values depend very much on the condition of the skin, local perfusion, and cardiac output. On the other hand, continuous intravascular pO2 monitoring does represent a relatively safe and convenient method of supervision. At this institute a cutaneous pCO2-sensor developed by the Bio-Electronics Department of F. Hoffmann-La Roche & Co. Ltd. with sensor temperatures of 41 degrees, 43 degrees, and 44 degrees C has been tested. The coefficients of correlation are 0.95 or even higher for all three sensor temperatures. At a sensor temperature of 41 degrees C the reaction velocity is markedly reduced. Accuracy and reaction velocity for the sensor temperatures of 43 degrees and 44 degrees C are equivalent, but at a temperature of 43 degrees C there are fewer and slighter skin reactions. The authors found a slight drift of 0.2--0.3 mm Hg/h. The dependence of cutaneous pCO2 on local perfusion and cardiac output also appears to be slight.

Adult↗
PubMed1982

Nosocomial infections in intensive care wards: a multicenter prospective study.

In a three-year prospective investigation, a total of 6,952 patients were investigated prospectively in nine intensive care wards and their rate of nosocomial infections was analysed. The frequency of the nosocomial infections varied between 3% and 27%. The most frequent nosocomial infections were urinary tract infections, sepsis, infections of the skin and of the subcutaneous tissue, pneumonia and wound infections. The most frequent causes of sepsis were ventilation pneumonia, venous catheters, wound infections and urinary tract infections. The pathogen spectrum was analysed. By specific control of infection with employment of an infection control nurse, the frequency of nosocomial infections on intensive care wards was lowered from 17.2% to 14.3% within one year in one of the hospitals.

Bacterial Infections↗
PubMed1979

[Respiratory failure and surgery].

The question whether a patient may be amenable to surgery involving anesthesia depends on many different factors and can only be answered by the anesthetist-surgeon team. The internist, on the other hand, will determine the degree of functional impairment of particular organ systems and cooperate in preoperative preparation of the patient. Patients with obstructive pulmonary disease are particularly at risk, especially during the postoperative period. The search for pulmonary symptoms is therefore extremly important. The limiting values given in medical literature are not absolute. Through preoperative therapy, the choice of suitable anesthetic methods and optimal postoperative care in an efficient intensive care unit, the risk of perioperative mortality and morbidity for this "poor risk patient" can be reduced almost to the level of the average surgical patient.

Anesthesia↗
PubMed1979

[Pseudocysts and retention cysts in acute and chronic pancreatitis (author's transl)].

42 cases of pancreatic cyst in acute (22 cases) pr chronic (20 cases) pancreatitis were seen between 1962 and 1976. Analysis of the case data revealed the following: (1) exact assignment of the cyst to acute or chronic pancreatitis is often possible only by long-term observation; (2) the cysts of chronic pancreatitis are not a uniform group: some (8 cases) apparently occurred in acute pancreatitis through necrotic episodes (pseudocysts), others (12 cases) by a retention mechanism; these "retention cysts" develop later in the course of chronic pancreatitis than the pseudocysts and produce a different clinical picture with better prognosis; (3) barium meal and retrograde cholangiopancreatography proved of diagnostic value' (4) if the cysts persist for more than six weeks operation is indicated because of the high incidence of complications.

Acute Disease↗
PubMed1979

The biosynthetic precursor of epidermal growth factor and the mechanism of its processing.

The biosynthesis of epidermal growth factor (EGF) was studied in mouse submaxillary glands incubated with L-[35S]cystine. EGF and EGF-like proteins were isolated from the gland homogenates by immunoprecipitation with anti-EGF antiserum. The major species appearing after short labeling periods is significantly larger (Mr, 9000) than EGF. The label in the Mr 9000 species plateaus after 1 hr whereas tha in EGF continuously increases. When glands are chased with unlabeled L-cystine after a brief period of labeling, the Mr 9000 peak decreases and a corresponding amount of label appears in EGF. The Mr 9000 species was isolated from boiled homogenates in which it accounts for approximately 1% of the total EGF content. It contains five of the six chymotryptic peptides of EGF and a sixth peptide which is a modified form of the COOH-terminal chymotryptic peptide of EGF. Of the arginyl esteropeptidases, gamma subunit of 7S nerve growth factor, beta-endopeptidase, trypsin, and EGF-binding protein, only the latter converts the isolated Mr 9000 species to EGF. The extrapeptide material released in the conversion comes from the COOH terminus of the Mr 9000 species. These results suggest that the Mr 9000 species is a biosynthetic precursor of EGF and that the EGF-binding protein is the specific intracellular cleaving enzyme that converts the precursor to EGF. In the process, the stable high molecular weight complex of EGF is formed.

Animals↗
PubMed1977

[Lipomatosis of the ileocecal valve].

Lipomatosis of the ileocecal valve is a diffuse infiltration of the submucous coat with fat cells. This syndrome is discussed on the basis of a personal observation and a review of the literature. The characteristic endoscopic picture is the overgrown, yellowish lips of Bauhin's valve prolapsing into the cecum, reminiscent of a uterine cervix. Coloscopy with biopsy is therefore the method of choice in assuring proper diagnosis. On the other hand, radiology cannot recognize the disease with certainty. Generally treatment of this benign syndrome is only necessary in the event of disturbances. As a surgical procedure ileocecal resection is suggested.

Aged↗