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Biomedical subjects

D J Martin

Publications and source records attributed to D J Martin.

At least 145 records · Page 8Linked to original sources
PubMed1985

Intraoperative changes in blood coagulation and thrombelastographic monitoring in liver transplantation.

The blood coagulation system of 66 consecutive patients undergoing consecutive liver transplantations was monitored by thrombelastograph and analytic coagulation profile. A poor preoperative coagulation state, decrease in levels of coagulation factors, progressive fibrinolysis, and whole blood clot lysis were observed during the preanhepatic and anhepatic stages of surgery. A further general decrease in coagulation factors and platelets, activation of fibrinolysis, and abrupt decrease in levels of factors V and VIII occurred before and with reperfusion of the homograft. Recovery of blood coagulability began 30-60 min after reperfusion of the graft liver, and coagulability had returned toward baseline values 2 hr after reperfusion. A positive correlation was shown between the variables of thrombelastography and those of the coagulation profile. Thrombelastography was shown to be a reliable and rapid monitoring system. Its use was associated with a 33% reduction of blood and fluid infusion volume, whereas blood coagulability was maintained without an increase in the number of blood product donors.

Adult↗
PubMed1984

A rare cause of spinal cord compression in childhood from intraspinal mesenchymal chondrosarcoma. A report of two cases and review of the literature.

Two children presented with acute spinal cord compression by primary and metastatic intraspinal mesenchymal chondrosarcoma, a rare pediatric malignancy. Patients with the primary intraspinal tumor usually present early and often respond well to combined surgery, irradiation and chemotherapy. Patients with intraspinal metastases present late in the course of their disease and their prognoses are poor.

Adolescent↗
PubMed1984

Pheochromocytoma in childhood: the important role of computed tomography in tumour localization.

The radiographic features of five children with nine pheochromocytomas are reviewed. Seven of eight lesions studied by CT were accurately localized. One 1.5 cm diameter extra-adrenal lesion, studied with a 2-min scanner, was not detected. Angiography failed to detect two of seven lesions. Fast scan and high resolution CT of the entire abdomen and pelvis is recommended as the initial modality of choice in children suspected of having pheochromocytoma. Chest CT need only be performed if a lesion is suspected on a chest radiograph or if the abdominal and pelvic CT reveal no lesion.

Adolescent↗
PubMed1984

Preliminary observations of the utility of portable NPT.

Nocturnal penile tumescence (NPT) has been utilized as an aid in the differential diagnosis of male erectile failure. The development of portable NPT monitors will broaden its applicability. Surprisingly, there are few data correlating sexual history interviews with NPT. In this study, 50 normal controls, 25 chronically ill patients with normal renal functioning, and 48 men with end-stage renal disease (ESRD) provided both detailed sexual histories and NPT tracings from portable monitors. In general, the data obtained from these two different sources of information were congruent. The presence of a sexual partner who could verify the sexual history enhanced the congruity. Portable NPT is probably useful at the very least as a screening technique in the assessment of male erectile failure.

Adult↗
PubMed1984

Periventricular infarction diagnosed by ultrasound: a postmortem correlation.

Ultrasound brain scans sometimes demonstrate increased echogenicity or cysts, or both, in the periventricular white matter, superolateral to the ventricle, in the most common site of periventricular infarction. Over 33 months, 23 preterm infants dying after 20 or more days of life were entered into this study. Superolateral echogenicity or cysts were found in 13 (57%) cases. Periventricular infarction was present at autopsy in 12 (52%) cases. Ultrasound accurately diagnosed the size, site, and extent of periventricular infarction in 78% of scans. Interpretive errors were made with poor-quality scans and with early and late studies. We conclude that sector ultrasound brain scans accurately diagnose major periventricular infarction. Hemorrhage into the site of infarction is not a prerequisite for diagnosis of periventricular infarction by ultrasound.

Autopsy↗
PubMed1984

Illusion of control for self and others in depressed and nondepressed college students.

Recently, it has been discovered that depressed people are less likely than nondepressed people to succumb to an "illusion of control" and judge that their actions influence outcomes that are objectively uncontrollable. This experiment examined the relationship between depression and susceptibility to the illusion of control for oneself and for others. Depressed and nondepressed college students were asked to judge either how much control they themselves had or how much control a male or female confederate had over a noncontingent, but positive, outcome. Replicating past findings on depression and judgments of control, depressed subjects judged relatively accurately that they exerted little control over the experimental outcome, whereas nondepressed subjects overestimated their personal control. Subjects' judgments of the confederates' control were a function of the subject's mood state and sex as well as of the confederate's sex. With one exception (depressed males in the male other condition), depressed subjects tended to overestimate the confederate's (male or female) control over the noncontingent outcome. Nondepressed females also judged that the confederate (male or female) exerted a high degree of control, thus succumbing to the illusion of control both for themselves and others. Nondepressed males, on the other hand, tended to judge more accurately that the confederate (particularly the female confederate) exerted little control and thus, succumbed to the illusion of control for themselves but not for others. These findings imply that an adequate understanding of depressive and nondepressive cognition requires an interpersonal as well as an intrapsychic perspective.

Adult↗
PubMed1984

Venous bypass in clinical liver transplantation.

A venous bypass technique (BP) that does not require the use of systemic anticoagulation is used routinely at our institution in all adult patients during the anhepatic phase of liver transplantation (LT). Complete cardiopulmonary profiles were obtained in a subset of 28 consecutive cases. During the anhepatic phase while on bypass, mean arterial pressure, central venous pressure, and pulmonary arterial wedge pressure were maintained at prehepatectomy levels. Oxygen consumption fell secondary to a decrease in temperature and the removal of the liver. Consequently, cardiac index fell without an increase in arterial-venous O2 content difference, reflecting adequate tissue oxygenation. Compared with 63 patients in a previous series given LT without bypass (NBP), the 57 total BP patients experienced better postoperative renal function (p less than 0.001), required less blood use during surgery (p less than 0.01), and had better survival 30 days after LT. The equivalency of 90-day survival in these groups results from the lack of effect of BP on the long-term survival of patients considered at high risk for metabolic reasons. BP patients at high risk for technical considerations, however, survived LT whereas NBP patients did not. BP offers other advantages important in establishing LT as a service-oriented procedure.

Adult↗
PubMed1984

Occult neuroblastoma presenting with opsomyoclonus: utility of computed tomography.

The clinical and radiographic findings in 10 children with neuroblastoma presenting with opsomyoclonus are described and the literature is reviewed. Children with opsomyoclonus are often a diagnostic dilemma, as they may not have a palpable tumor or increased urinary catecholamines. Computed tomography (CT) is the most sensitive imaging method in locating tumors (100%) compared with plain radiography of the chest and abdomen (sensitivity 40%), excretory urography (50%), and 99mTc radionuclide bone scans (50%). The use of body CT significantly shortened the interval between initial presentation and final diagnosis and avoided multiple hospitalizations and unnecessary investigations for patients with persistent opsomyoclonus. Since most neuroblastomas are solitary lesions that may arise in the adrenal glands or along the sympathetic chain from the neck down into the pelvis, our policy is to use plain radiography, sonography, and 99mTc methylene diphosphonate (MDP) bone scans for the preliminary investigation of patients with opsomyoclonus. Body CT can then be tailored to suit the needs of the individual patients.

Abdominal Neoplasms↗
PubMed1983

NH2-terminal processing of Drosophila melanogaster actin. Sequential removal of two amino acids.

Class II actins, such as Drosophila and mammalian skeletal muscle actins, have genes that code for a Met-X-Asp NH2 terminus where X is usually cysteine. These actins have an Ac-Asp NH2 terminus so two amino acids must be removed. To determine the nature of this processing, we labeled Drosophila Schneider L-2 cells with [35S]methionine or cysteine, isolated the actin, and analyzed the NH2-terminal actin tryptic peptides and their thermolysin digestion products. After a 4-h labeling period, we detected completed actin polypeptide chains with either an unblocked Asp or an Ac-Asp NH2 terminus. No intermediate with an NH2-terminal Cys or Met could be demonstrated. If, however, Drosophila mRNA was translated in a mRNA-dependent rabbit reticulocyte lysate system, an additional 43-kDa actin intermediate was observed. On the basis of thermolysin digestion studies and experiments using mild acid hydrolysis of a labeled actin NH2-terminal tryptic peptide fragment, we identified this intermediate as having an Ac-Cys-Asp NH2 terminus. In a time-dependent fashion, Ac-Cys was removed generating actin with an exposed NH2-terminal Asp which was subsequently acetylated to produce the mature form of actin. The removal of Met and the acetylation of Cys may occur early in translation while the nascent polypeptide chain is still attached to the ribosome. Subsequent processing occurs following completion of the synthesis of the actin polypeptide. The removal of Ac-Cys from Drosophila actin is thus similar to removal of Ac-Met from the NH2 terminus of class I actins although in the case of the class II actins, it is the second amino acid that is removed as an acetylated species.

Actins↗
PubMed1983

NH2-terminal processing of actin in mouse L-cells in vivo.

When Dictyostellium discoideum actin is synthesized in vitro, it is made as a 43,000-dalton polypeptide with an NH2-terminal N-acetylmethionine. The acetylmethionine is then cleaved post-translationally, and the new NH2-terminal aspartic acid is acetylated to give the mature form of actin. Inhibition of methionine acetylation prevents methionine cleavage (Redman, K., and Rubenstein, P. (1981) J. Biol. Chem. 256, 13226-13229). In this paper, we describe the results of experiments designed to discover whether this novel actin processing pathway is peculiar to the rabbit reticulocyte lysate system or whether it is utilized by mammalian cells in vivo as well. We show that in mouse L-929 cells, actin is made as a 43,000-dalton protein with an NH2-terminal N-acylmethionine residue. Experiments using thin layer chromatography and digestion of the acylmethionine residue with hog kidney acylase I demonstrate that the acyl group is an acetyl residue. Pulse-chase experiments show that over the course of 1 h, this precursor is transformed first to an actin with a free NH2-terminal aspartic acid and is subsequently converted to mature L-cell actin with an acetylaspartic acid NH2 terminus. The half-life of the initial actin precursor in the cell appears to be approximately 12-15 min. These studies demonstrate the existence of this novel actin processing pathway in vivo and suggest that it is used for those actins where, in the gene, the initiator methionine codon directly precedes the codon for aspartic or glutamic acids, the residues normally found at the actin NH2 terminus.

Actins↗
PubMed1983

Extragonadal endodermal sinus tumors in children: a review of 24 cases.

Endodermal sinus tumors (EST) are highly malignant lesions with a tendency to recur locally and with a high incidence of metastatic disease at the time of diagnosis. The clinical and radiographic spectra of 24 patients with extragonadal EST are reported. There were 17 females and seven males and the mean age of presentation was 21 months. The primary lesion occurred in the sacrococcygeal region in 16 patients; in the vagina in two patients; in the anterior mediastinum in two patients; and in the bladder, liver, nasopharynx and posterior cranial fossa in one patient each. Computed tomography (CT) is the most accurate study in delineating the extent of primary lesions particularly in the pelvis and head and neck and also for demonstrating metastatic disease in the lungs. Significant improvement in survival rates is obtained with a combination of surgery, chemotherapy and radiotherapy.

Child, Preschool↗
PubMed1983

Pancreatic carcinoma in a neonate.

The clinical and radiographic findings in a neonate with adenocarcinoma of the head of the pancreas are presented. CT revealed the mass to be well defined, with an inhomogeneous density before and after intravenous contrast enhancement. Ultrasound revealed the mass to be mainly densely echogenic with small, irregular echo-free areas. The portal vein was intimately applied to the posterior aspect of the mass. The literature concerning adenocarcinoma of the pancreas in the pediatric age group is reviewed.

Adenocarcinoma↗
PubMed1983

Cirrhosis: an unusual pattern of enhancement on CT.

A previously unreported pattern of enhancement of the liver on CT in a 7-month-old female with cirrhosis is illustrated. Precontrast scans showed the liver to have a normal homogeneous density throughout. Scans performed immediately after rapid bolus injection of contrast showed an uneven enhancement of the entire liver. Bands of enhancing tissue (thought to represent vascular fibrous tissue) surrounded more extensive areas that enhanced less markedly. Delayed post-injection scans revealed again an even level of density throughout the liver.

Barium Sulfate↗
PubMed1983

Hypoxic/ischaemic cerebral injury in the neonatal brain. A report of sonographic features with computed tomographic correlation.

Ultrasound has been used in 11 neonates whose history or clinical features suggested the possibility of hypoxic/ischaemic lesions. The ultrasound findings were correlated with computed tomographic findings in nine infants and with pathological findings in two. On ultrasound scan, areas of increased echoes represented both hypoxic/ischaemic and haemorrhagic lesions. However, the distinction between them could not be made with certainty. Cystic changes were shown clearly by ultrasound as were cerebral vascular pulsations in and adjacent to the areas of increased echoes. With computed tomography, hypoxic/ischaemic lesions were represented by areas of decreased density and haemorrhagic lesions by areas of increased density. Computed tomography failed to clearly demonstrate the cystic changes. Three types of lesions, viz. diffuse, focal and periventricular were based on the location of brain injury, the former two occurring in term infants and the latter in premature infants. Ultrasound has been shown to be of value for definition of the site and extent of hypoxic/ischaemic cerebral lesions in the newborn and for observation of their evolution.

Brain Ischemia↗
PubMed1983

Biliary disease in metachromatic leukodystrophy.

This paper illustrates the previously unreported sonographic changes in the biliary tract in metachromatic leukodystrophy (MLD). Gallbladder wall thickening due to sulfatide deposition, intraluminal globules of sulfatide or papillomatosis may cause symptoms referrable to the biliary tract in these patients. A series of patients whom we have studied is briefly alluded to in order to bring to the attention of the radiologist MLD as a rare cause of biliary disease in children.

Adolescent↗
PubMed1983

Renal cell carcinoma in the first two decades of life.

Renal cell carcinoma occurs rarely in the first two decades of life. This paper reviews the clinical and radiographic features of 17 such patients (10F: 7M, mean age = 12 years) seen in a 24 year period. The almost equal sex incidence contrasts with the male preponderance in adults. All patients presented with symptoms and signs referable to the primary lesion. In comparison to Wilms' tumor, renal cell carcinoma in childhood and adolescence usually presents with a smaller abdominal mass which is frequently not palpable or visible on plain abdominal radiographs. Ultrasound and CT showed non-specific solid intrarenal masses. This rare tumor of childhood should be included in the differential diagnosis of intrarenal mass lesions, particularly in older children with hematuria and renal calcification on plain radiographs. One child in this series had tuberous sclerosis. The prognosis depends on the stage of disease at presentation.

Adenocarcinoma↗
PubMed1983

Cardiac metastases from osteosarcoma. A report of two cases.

Two children who developed cardiac metastases from osteogenic sarcoma are described, and the value of computed tomography in making an antemortem diagnosis is illustrated. Computed tomographic images with a narrow window width will reveal the presence of calcification within the cardiac metastases. Images in this mode should always be studied in patients with osteogenic sarcoma who are undergoing chest computed tomography scans to detect pulmonary metastases.

Adolescent↗