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Biomedical subjects

J Barrett

Publications and source records attributed to J Barrett.

At least 271 records · Page 15Linked to original sources
PubMed1988

Hymenolepis diminuta: lack of sulphate activation and sulphotransferase activity.

There is no evidence that Hymenolepis diminuta can carry out sulphoconjugation reactions. Neither whole worms nor worm extracts were able to sulphate 4-methylumbelliferone. No sulphotransferase activity could be demonstrated in H. diminuta using a variety of substrates, nor was H. diminuta capable of synthesising the sulphate donor 3'-phosphoadenosine-5'-phosphosulphate from ATP and inorganic sulphate. Possible alternative sources of active sulphate in this parasite are discussed.

Adenosine Triphosphate↗
PubMed1988

Nucleoside uptake by Trichomonas vaginalis.

A rapid sampling technique was used to follow nucleoside uptake by Trichomonas vaginalis. The results indicated that nucleoside uptake is biphasic with time. Adenosine, guanosine, and uridine uptake is carrier mediated, transported substrate is rapidly metabolised to nucleotides. Two separate carriers appear to exist, one which transports all nucleosides and a second which transports adenosine, guanosine and uridine. Both carriers have more than one binding site for nucleosides. The first carrier has sites for adenosine and pyrimidine nucleosides, and a separate site for purine nucleosides. The second carrier has a site for adenosine and uridine and a separate site for guanosine. Adenosine uptake could not be completely inhibited by nitrobenzylthionucleosides. The rate of nucleoside uptake by T. vaginalis is sufficient to sustain growth.

Adenosine↗
PubMed1988

Analysis of 18 recent cases of penetrating injuries to the common and internal carotid arteries.

Penetrating injuries to the common and internal carotid artery carry the unique potential for irreversible neurologic damage, respiratory collapse, and exsanguination. This study analyzes a recent 4 year experience with 18 cases of penetrating injury to the carotid artery to identify the factors influencing surgical decision-making, perioperative complications, and mortality. Sixteen patients with acute respiratory distress required emergent airway intubation. Three patients in hemorrhagic shock were brought directly to the operating room; the remaining 15 underwent emergency carotid arteriography. Three patients with multiple intramediastinal vascular injuries exsanguinated on the operating table before hemorrhage could be controlled. There were no deaths or neurologic complications in the 14 surviving patients who had an operation on the carotid artery, including 2 patients treated by internal carotid artery ligation. Early control of the airway was the most common initial requirement in this group of patients. Judicious use of preoperative arteriography was thought to facilitate the operative approach in selected patients. A flexible surgical approach to the damaged carotid artery is essential based on the patient's hemodynamic status, degree of neurologic impairment, and nature and extent of arterial damage.

Adolescent↗
PubMed1988

Cysteine metabolism in the cestode Hymenolepis diminuta.

The major pathways for cysteine catabolism in Hymenolepis diminuta have been investigated. The parasite has an active cystathionine-beta-synthase and, as in other tissues, this enzyme has a wide substrate specificity. However, the enzyme from H. diminuta differs significantly from the mammalian enzyme in showing a high serine sulphydrase activity and a high serine lyase activity. There was only low gamma-cystathionase activity in H. diminuta and again the enzyme showed a range of substrate specificities. Cysteine aminotransferase activity was readily demonstrated in the tapeworm, but there was no evidence for 3-mercaptopyruvate sulphotransferase activity. An oxidative pathway for cysteine catabolism in H. diminuta was shown by the presence of cysteine dioxygenase and cysteine sulphinate transaminase. The properties of the helminth cysteine dioxygenase were very similar to those of rat liver. H. diminuta was able to reduce cystine to cysteine via a glutathione-cysteine transhydrogenase system.

Animals↗
PubMed1988

Determinants of delayed gastric emptying in anorexia nervosa and bulimia nervosa.

Gastric emptying was measured using a gamma camera in 22 patients with anorexia nervosa, in 10 patients of normal or high weight with bulimia nervosa and in 10 controls. Patients with anorexia nervosa were tested (1) while underweight and selecting their own diet (10 patients); (2) underweight, but receiving an adequate diet on an inpatient unit (refeeding diet) (12 patients); and (3) under refeeding diet conditions after weight gain (eight patients). Three meals, each labelled with technetium 99m-sulphur colloid, 3.7 MBq were used: (1) a mixed solid meal containing labelled poached egg; (2) 200 ml d-glucose solution, 0.5 kcal/ml, and (3) 200 ml physiological saline. Only gastric emptying rates of the solid meal and glucose solution were significantly delayed. Gastric emptying of saline was normal. The gastric disturbance was confined to patients with anorexia nervosa selecting their own diet. Patients receiving adequate nutrition on the ward had normal gastric emptying and weight gain in this group had no significant effect on emptying. Slow emptying was observed in patients who maintained a low weight solely by food restriction as well as in patients whose anorexia nervosa was complicated by episodes of bulimia. Thus, slow gastric emptying occurred when the quantity of food reaching the duodenum was sufficiently reduced to result in severe weight loss. Moreover, abnormal gastric emptying was seen only after the two meals that contained calories and were hypertonic to plasma, either of which properties could mediate the disturbance. Gastric emptying in bulimia nervosa was normal. Slow gastric emptying could exacerbate undereating in starving patients with anorexia nervosa by enhancing satiety.

Adult↗
PubMed1988

Head injury and hemorrhagic shock: studies of the blood brain barrier and intracranial pressure after resuscitation with normal saline solution, 3% saline solution, and dextran-40.

The effect of fluid resuscitation from hemorrhagic shock on cerebral edema, intracranial pressure (ICP), and blood brain barrier function was investigated in the presence of a simulated head injury. Beagle dogs were anesthetized and ICP was measured via a right subarachnoid bolt while a contralateral epidural balloon was inflated in the left hemicranium to mimic a closed head injury. Forty percent of the dogs' blood was shed and the shock state was maintained for 1 hour. Resuscitation was initiated with shed blood and a volume of either normal saline solution (NS, n = 5), 10% dextran-40 (D-40, n = 6), or hypertonic (3%) saline solution (HS, n = 6) equal to the amount of shed blood. Evans blue solution was infused intravenously, and intravascular volume was then maintained with normal saline solution. Control (n = 5) dogs did not undergo shock, but received equivalent volumes of normal saline solution and Evans blue solution. The dogs were killed after 2 hours of resuscitation, and the brains were removed, weighed, and fixed in formalin. The average intracranial pressure value after epidural balloon inflation was 18.6 +/- 0.80 mm Hg and decreased equally in all groups during the shock period, averaging 10.8 +/- 1.24 mm Hg at the end of the shock period. Fluid resuscitation markedly elevated ICP in the NS and D-40 groups, reaching maximal values of 46.6 +/- 12.11 mm Hg and 45.3 +/- 28.95 mm Hg, respectively. Maximal ICP values in control and HS groups measured 21.8 +/- 1.36 mm Hg and 15.8 +/- 2.04 mm Hg, respectively (p less than 0.25 for HS versus NS control). Wet brain weights were significantly less in the HS group compared with either NS or D-40 groups (p less than 0.05). Coronal sections of fixed HS brains showed deep cortical Evans blue staining on the side of balloon injury. Therefore, in the presence of an intracranial mass lesion, resuscitation with hypertonic (3%) saline solution is accompanied by lower ICP values and less cerebral edema than is isotonic saline or colloid resuscitation. Blood brain barrier function is not restored by hypertonic saline solution resuscitation.

Animals↗
PubMed1987

Heligmosomoides polygyrus: peroxidase activity.

Peroxidase activity in Heligmosomoides polygyrus was located primarily in the mitochondrion. The enzyme was active with a range of organic and inorganic electron donors and, in addition to hydrogen peroxide, it could utilize cumene peroxide, but the highest activity was obtained with linoleic acid peroxide. The effects of electron chain substrates and inhibitors on H. polygyrus mitochondrial peroxidase activity was consistent with the enzyme being linked functionally to cytochrome c, although in vivo, this may not be the only electron donor. The interaction of the peroxidase with electron transport is discussed.

Animals↗
PubMed1987

Psychiatric symptoms in the elderly in a primary care practice.

During a 15-month period in a rural group medical practice 1063 patients of four general internists completed a 49-item version of the Hopkins Symptom Check List (HSCL). This version of the HSCL measured symptoms of depression, anxiety, phobic anxiety, hostility, and interpersonal sensitivity. In comparison to younger groups, the elderly patients reported decreased symptomatology on all HSCL scales except the phobic anxiety scale. These differences could be due to a reporting effect, selective migration or mortality, a cohort effect, or they could reflect a true age effect, the view favored by the authors.

Aged↗
PubMed1987

An unusual presentation of Brown-Sequard syndrome.

We report the case of a man with Brown-Sequard syndrome following a fall in which he sustained fractures of the thoracic and lumbosacral spine. Despite characteristic neurological findings, the diagnosis was delayed due to the absence of history of penetrating spinal trauma and incorrect attribution of unilateral-like weakness and numbness to lumbosacral trauma. A directed history and examination revealed that the patient was stabbed in the back with a penknife while leaving a bus and stepped down onto a paralyzed leg, which collapsed beneath him. The patient was given an antibiotic, underwent a negative peritoneal lavage, and had myelography and nerve conduction velocity confirmatory for Brown-Sequard syndrome. With rehabilitation he became ambulatory with a cane one month after the stabbing.

Accidental Falls↗
PubMed1987

The early fate of venous repair after civilian vascular trauma. A clinical, hemodynamic, and venographic assessment.

Repair of major venous injuries of the extremities has been advocated to improve limb salvage rates and to prevent the early and late sequelae of venous interruption. The contribution of venous repair to the surgical outcome remains controversial, however, in part because the fate of venous reconstruction has previously not been well defined. The current study was done to determine the early patency rate of venous repair, to compare the accuracy of various methods used to assess venous patency, and to analyze the relationship between early venous patency and surgical outcome. During a recent 27-month period, 36 patients with major extremity venous injuries were treated by venous reconstruction; 34 patients (94%) had an associated major arterial injury that also required repair. Venous repair was performed in the upper extremity (22%) as well as the lower extremity (78%) using various reconstructive methods, including lateral repair (17%), end-to-end anastomosis (11%), autogenous vein patching (25%), interposition autogenous vein grafting (42%), and panelled autogenous vein grafting (6%). After operation, venous repair patency was evaluated by clinical examination, impedence plethysmography, and Doppler ultrasonography, and contrast venography. There were no perioperative deaths in these 36 patients. The limb salvage rate was 100% and all 34 major arterial repairs were patent at the time of hospital discharge. Venography performed on the seventh postoperative day demonstrated that 14 venous repairs had thrombosed (39%) and that 22 had remained patent (61%). Local venous repair had a significantly lower thrombosis rate (21%) than those requiring interposition vein grafting (59%) (p less than 0.03). Compared with venography, the clinical evaluation was 67% accurate in the assessment of venous repair patency, and the noninvasive examination was 53% accurate. In conclusion, a substantial percentage of venous repairs will thrombose in the postoperative period, especially if interposition vein grafting is used. However, in this series limb salvage was not adversely influenced by an unexpectedly high rate of venous repair thrombosis. In addition, clinical evaluation and noninvasive testing did not provide an accurate assessment of venous patency after venous repair.

Adolescent↗
PubMed1987

Needle biopsy evaluation of class II major histocompatibility complex antigen expression for the differential diagnosis of cyclosporine nephrotoxicity from kidney graft rejection.

Twenty needle biopsies from 14 patients were taken at times of renal dysfunction, and frozen sections were stained for class I and class II major histocompatibility complex (MHC) antigen expression using the immunoperoxidase technique and monomorphic mouse monoclonal antibodies. Eight of the 9 biopsies taken during periods of dysfunction attributed to cyclosporine toxicity had normal levels of class II expression. In contrast, 9 of the 10 biopsies taken during episodes of rejection had easily recognized increases in class II expression. In the one case where no definite clinical diagnosis was possible, no class II induction was present. Class I levels were less definitive but tended to be markedly raised in the cases of rejection, and only mildly raised in the cases of nephrotoxicity. Biopsy results can be available within 1 1/2-2 hr. The test is therefore likely to be of value in the correct diagnosis of the cause of renal dysfunction and thereby improve the management of cyclosporine-treated renal transplant patients.

Antibodies, Monoclonal↗
PubMed1987

ABH and Lewis antigen and antibody expression after bone marrow transplantation.

We have tested 10 bone marrow transplant donors and recipients for ABH and Lewis antigens and ABH antibodies. Two group A2 recipients stably engrafted with group O marrow produced anti-A1. Small quantities of recipient-type ABH substance were found on the posttransplant erythrocytes in cases where the recipient was a secretor but not in a single nonsecretor recipient. Lewis antigens were always of recipient type. The incidence of graft-versus-host disease and graft rejection were similar in 41 patients who received ABO-mismatched and 61 patients who received ABO-matched grafts.

ABO Blood-Group System↗
PubMed1987

Apolipoproteins AI, AII, and CI stimulate placental lactogen release from human placental tissue. A novel action of high density lipoprotein apolipoproteins.

High density lipoproteins (HDL) stimulated a dose-dependent increase in the release of placental lactogen (hPL) from human placental explants. The stimulation was not prevented by delipidation of HDL but was completely blocked by tryptic digestion. Delipidated apolipoproteins (Apo) AI, AII, and CI also stimulated hPL release but other apolipoproteins were without effect. HDL and Apo CI had no effects on the release of luteinizing hormone and follicle-stimulating hormone from rat pituitary cells or the release of prolactin from human decidual cells. Because placental cells have specific HDL receptors and plasma HDL concentrations increase during pregnancy, these results strongly suggest a role for HDL in the regulation of hPL release during pregnancy possibly independent of their usual role in plasma lipid transport.

Apolipoprotein A-I↗