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Biomedical subjects

K Crowley

Publications and source records attributed to K Crowley.

29 records · Page 2Linked to original sources
PubMed1994

Schwannoma (neurilemoma) with malignant transformation. A rare, distinctive peripheral nerve tumor.

Malignant transformation of a schwannoma (neurilemoma) is an exceedingly rare event. We describe two cases with such change and review the reported purported examples. The tumors in our patients involved a finger and pelvis. Sex, age, and clinical follow-up were available for only the second case, involving a 31-year-old man who died with recurrent and metastatic tumor. Seven acceptable cases were found in the literature. Analysis of the nine cases of schwannoma with malignant transformation showed no sex predilection, but revealed a tumor differing significantly from conventional malignant peripheral nerve sheath tumors. The mean age (56 years) was two decades older, no patient had neurofibromatosis, in four cases there was a years-long history of an antecedent mass, and in none of the cases was the malignant component an interlacing, fasciculated spindle-cell tumor. Rather, the malignant component was commonly purely epithelioid (seven of nine cases). In the two other cases, cells of the malignant component had neuroepithelial features. The prognosis for patients with schwannomas undergoing malignant change is poor. Five of eight patients with follow-up (62%) died of disease with either residual (one patient) or metastatic tumor (four patients).

Adult↗
PubMed1991

The microgenetic method. A direct means for studying cognitive development.

Progress in understanding cognitive developmental change mechanisms requires methods that yield detailed data about particular changes. The microgenetic method is an approach that can yield such data. It involves (a) observations of individual children throughout the period of the change, (b) a high density of observations relative to the rate of change within that period, and (c) intensive trial-by-trial analyses intended to infer the processes that gave rise to the change. This approach can illuminate both qualitative and quantitative aspects of change, indicate the conditions under which changes occur, and yield otherwise unobtainable information about short-lived transition strategies. The cost in time and effort of such studies is often high, but the value of the information about change can more than justify the cost.

Achievement↗
PubMed1990

Serum concentrations of prilocaine following retrobulbar block.

Retrobulbar block for eye surgery is associated with adverse reactions. We performed retrobulbar block in 10 patients using prilocaine (Citanest) and found mean (SD) peak serum concentrations of 851 (165.6) ng ml-1 (range 540-1100 mg ml-1). Peak serum concentrations occurred 3-7 min after the end of administration of the block, and in all cases were less than those associated with toxicity.

Aged↗
PubMed1990

Diuretics after transurethral prostatectomy: a double-blind controlled trial comparing frusemide and mannitol.

Mannitol and frusemide were compared in a randomized, controlled, double-blind trial for their effects in promoting diuresis after prostatectomy and on indices of water intoxication. The drugs had comparable diuretic effects. Sodium loss was greater with frusemide, contributing to sodium depletion after operation. Administration of frusemide was associated with more frequent need for i.v. volume expansion after operation. Plasma osmolality was greater with mannitol (289 (SD 4.2 mosmol kg-1 at 1 h after operation and 285 (5.3) mosmol kg-1 at 4 h after operation) than with frusemide (282 (7.1) mosmol kg-1 and 279 (6.7) mosmol kg-1, respectively) (P less than 0.05). Plasma concentration of sodium was significantly greater with mannitol (136.9 (3.1) mmol litre-1) than with frusemide (134.4 (2.8) mmol litre-1) only on the morning after surgery (P less than 0.05). Mannitol is an effective alternative to frusemide in inducing diuresis after prostatectomy, and may protect against water intoxication.

Diuresis↗
PubMed1990

Bedtime buys.

Explore the source record for details and available documents.

Clothing↗
PubMed1990

Septicaemia and the prevention of multiorgan failure--the intensive care perspective.

Septicaemia frequently presents without "classic" signs of infection--tachypnoea, hypotension and confusion are the commonest features. The mortality rate is 40 to 80% and in intensive care units, septicaemia accounts for 70% of all deaths. Despite the use of antimicrobial drugs to which the offending organism is sensitive, patients are still dying. Effects on distant organ systems are due to "Mediators". "Microvascular Failure" resulting in tissue hypoxia is the unifying hypothesis of multiple organ failure in septicaemia. Mortality is correlated with the number of organ system failures. Supportive management is aimed at prevention of organ failure--manipulation of the circulation being the central key. Intravascular volume expansion, vasoactive drugs, mechanical ventilation and invasive monitoring are the means. Antimicrobial therapy must be guided by 'best guess' approach with multiple agents until isolation of the offending organism can recommend specific therapy. Aggressive surgical drainage or excision, is particularly applicable in abdominal sepsis. Several adjunctive therapies aimed at mediators of sepsis, are as yet experimental.

Critical Care↗
PubMed1989

Barbiturate anesthetics inhibit thromboxane-, potassium-, but not angiotensin-induced pulmonary vasoconstriction.

Administration of the oxidant lipid peroxide tertiary butyl hydroperoxide (t-bu-OOH) in the isolated rabbit lung leads to acute pulmonary vasoconstriction, which is caused by the synthesis of thromboxane. The inhalational anesthetics, halothane, nitrous oxide, and cyclopropane, markedly enhance t-bu-OOH-induced pulmonary vasoconstriction and thromboxane production. The effects of the intravenous (iv) barbiturates thiopental and pentobarbital on t-bu-OOH-induced vasoconstriction were studied. Thiopental completely and pentobarbital partially blocked t-bu-OOH-induced vasoconstriction. Thiopental inhibited t-bu-OOH-induced synthesis of thromboxane and prostacyclin but pentobarbital did not. This inhibitory action of thiopental may be due to its antioxidant properties because similar inhibition has been observed of t-bu-OOH-induced thromboxane production with the antioxidants, vitamin E, or butylated hydroxylanisole. Thiopental and pentobarbital also inhibited the vasoconstriction induced by a thromboxane analog, epoxymethano prostaglandin H2 (U46619). Finally, both barbiturates partially inhibited the pulmonary vasoconstriction caused by potassium chloride, which requires calcium entry, but they did not inhibit the constriction caused by angiotensin II, which does not require calcium entry. These results suggest that pentobarbital and thiopental may block pulmonary vasoconstriction by inhibiting calcium entry.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMedDate not supplied

Acute renal failure in orthotopic liver transplantation.

Acute renal failure (ARF) is a frequent complication of orthotopic liver transplantation (OLT) and is a major cause of mortality and morbidity. We report the incidence, management and outcome of ARF in OLT patients during the first year of a liver transplant programme.

Acute Kidney Injury↗
PubMedDate not supplied

Is repeat laparotomy of value in patients with suspected intra-abdominal sepsis in the intensive care unit?

The management of patients with suspected post laparotomy intra-abdominal sepsis poses a major therapeutic challenge to clinicians. The mortality is high and the optimal interventional modality remains ill-defined. We define the incidence, diagnostic methodology, pre- and postoperative findings and outcome of patients going from the intensive care unit for a repeat laparotomy in search of abdominal sepsis over a one year period. Fifteen patients were included with an overall mortality of 60 percent. In 6 cases more than one relaparotomy was performed with a mortality of 50 percent. Sepsis was found in 14 of the 15 cases with a mortality of 57 percent and the patient with a normal relaparotomy died. The primary surgery was elective in 26 percent of cases and the mortality was 50 percent. All the non-survivors required mechanical ventilation, inotropic support and continuous veno-veno haemodialysis while the survivors required less organ support. Radiological assessment (ultrasound scan and CT scan) were no better at predicting an abnormal relaparotomy than clinical assessment. Higher mortality rates were associated with increasing age and multi-system organ failure (p < 0.05).

Abdomen↗
PubMedDate not supplied

Explanation and generalization in young children's strategy learning.

Children often learn new problem-solving strategies by observing examples of other people's problem-solving. When children learn a new strategy through observation and also explain the new strategy to themselves, they generalize the strategy more widely than children who learn a new strategy but do not explain. We tested three hypothesized mechanisms through which explanations might facilitate strategy generalization: more accurate recall of the new strategy's procedures; increased selection of the new strategy over competing strategies; or more effective management of the new strategy's goal structure. Findings supported the third mechanism: Explanations facilitated generalization through the creation of novel goal structures that enabled children to persist in use of the new strategy despite potential interference from competing strategies. The facilitative effect of explanation did vary with children's age and did not vary between explanations children created by themselves versus explanations they learned from the experimenter.

Analysis of Variance↗