Search PubMed⌕ Search

Biomedical subjects

R Gordon

Publications and source records attributed to R Gordon.

At least 109 records · Page 6Linked to original sources
PubMed1993

Detection of renin mRNA in aldosterone-producing adenomas by polymerase chain reaction.

1. Ribonucleic acid (RNA) was extracted from two normal human adrenal cortices and from five aldosterone-producing adenomas (APA). 2. The five APA could be categorized, on the basis of in vivo aldosterone responsiveness to angiotensin infusion and upright posture, into two APA responsive to both stimuli, two responsive only to angiotensin infusion, and one unresponsive to either stimulus. 3. RNA was reverse transcribed and coamplified by polymerase chain reaction (PCR) with an internal standard of renin complementary DNA (cDNA) containing a 60 base pair insertion. Renin mRNA in the APA was compared with normal adrenals. 4. Renin mRNA was greater than normal in the two APA responsive to both stimuli and less than, or similar to normal, in the two APA responsive only to angiotensin infusion. Renin mRNA was also less than, or similar to normal, in the APA unresponsive to either stimulus. 5. These findings support a possible role for adrenal renin in the development and biochemical behaviour of angiotensin-responsive APA.

Adenoma↗
PubMed1993

Use of capnography for assessment of the adequacy of alveolar ventilation during weaning from mechanical ventilation.

A prospective study was conducted to determine the reliability of noninvasive end-tidal CO2 (PETCO2) monitoring as a reflection of arterial CO2 tension (PaCO2) during weaning from mechanical ventilation (MV). Simultaneous PaCO2 and PETCO2 determinations were compared during MV and again during a spontaneous breathing trial just before returning the patient to MV. Three groups of patients recovering from acute respiratory failure were evaluated. Group 1 consisted of 16 patients (28 observations) without parenchymal lung disease. Group 2 consisted of 22 patients (31 observations) with alveolar filling diseases. Group 3 was composed of 13 patients (22 observations) with emphysema. Significant Pearson correlation coefficients were demonstrated between PaCO2 and PETCO2 during both MV and spontaneous breathing in all three groups. Significant correlation was also demonstrated between the change in PaCO2 and the change in PETCO2 associated with weaning for each group; however, the degree of correlation varied between groups. Our data suggest that capnography offers a reasonable estimate of PaCO2 and changes in PaCO2 during weaning in patients without parenchymal lung disease. However, PETCO2 is less sensitive to changes in PaCO2 for patients with parenchymal lung disease, particularly patients with emphysema. Interpretation of capnographic data requires a full understanding of its limitations. An approach to capnographic monitoring during weaning is discussed.

Aged↗
PubMed1993

Pentostatin increases the acute toxicity of high dose cyclophosphamide.

One dose of pentostatin was added to a standard cyclophosphamide (CY) based transplant regimen in two patients in an attempt to decrease the rate of non-engraftment in haploidentical allogeneic BMT. Despite a normal cardiac history and evaluation prior to transplant, both patients suffered fatal cardiac toxicity within 48 h of receiving the chemotherapy. This phenomenon was further investigated in an animal model. Laboratory rats were treated with progressive doses of CY in a range that produces acute cardiac toxicity. Successive groups of rats were treated with either pentostatin or fludarabine and CY at 400 mg/kg. Neither pentostatin nor fludarabine alone produced early mortality. However, a marked increase in early mortality was noted in those animals treated with pentostatin and high-dose CY. The addition of fludarabine did not increase the early toxicity of CY. Autopsy revealed no gross or microscopic abnormalities in the animals. The implications of adding agents that interfere with adenosine metabolism to CY based transplant regimens is discussed.

Adult↗
PubMed1993

Effects of felbamate and other anticonvulsant drugs in two models of status epilepticus in the rat.

Felbamate was compared with several antiepileptic drugs for protective effects in two rat models of status epilepticus. Felbamate was ten times more potent against pilocarpine-induced seizures in lithium-treated rats than in lithium-free animals. Diazepam, valproate and phenobarbital were effective in both the high dose pilocarpine and lithium-pilocarpine models. On the other hand, phenytoin was ineffective in both models, whereas carbamazepine displayed protective effects only in the lithium-pilocarpine model.

Animals↗
PubMed1993

Chronic recurrent esophageal strictures treated with balloon dilation in children with autosomal recessive epidermolysis bullosa dystrophica.

Two children (8- and 17-yr old) with autosomal recessive epidermolysis bullosa dystrophica and chronic esophageal strictures were treated with repeated balloon dilations. General anesthesia was by face mask adapted specifically for this procedure, with careful attention to avoid skin and mucus membrane damage. A balloon dilator positioned fluoroscopically over an angiographic guidewire was gently inflated until narrowings resolved. Dilations have been performed every 1-11 [4.3 +/- 3.2 (mean +/- SD)] months in the younger patient over the last 4.3 yr, and every 8-20 (14.5 +/- 5.9) months in the older patient over the last 4.8 yr, without serious complications. Both patients were able to swallow normal foods following dilations. Repeated balloon dilations of esophageal strictures in patients with epidermolysis bullosa dystrophica can be done safely. Further studies are indicated to determine its effectiveness and appropriateness as an alternative to colonic interposition.

Adolescent↗
PubMed1992

Cytomegalovirus infection of the upper gastrointestinal tract following liver transplantation--incidence, location, and severity in cyclosporine- and FK506-treated patients.

One hundred and forty randomly selected liver transplant recipients were studied before and after primary orthotopic liver transplantation for the presence or absence of CMV enteritis. Following OLTx, 65 patients were treated with cyclosporine A and 75 were treated with FK506. The two groups were similar with regard to the incidence, location, and outcome of their upper gastrointestinal CMV infection. Prior to OLTx, only one patient had evidence of enteric CMV infection. The incidence of CMV enteritis post-OLTx was 27.7% in the CsA-treated group and 20% in the FK-treated group. During the first posttransplant month, no patient in the FK-treated group developed CMV enteritis, compared with 11.5% of the patients who were treated with CsA (P less than 0.05). Gastric CMV was found in over 80% of those positive for any organ in either group. In addition to CMV infection of the upper gastrointestinal tract, clinically evident CMV disease involved more nonenteric organs in the CsA-treated group than in the FK-treated group. In the CsA-treated group, CMV-negative patients had a statistically higher 1-year survival rate (100%) than CMV-positive patients (77.8%) (P less than 0.05). In the FK-treated group, no difference in survival was observed between CMV-positive or CMV-negative cases at 1 year. Of the patients on CsA, 20% received OKT3 for persistent rejection, as compared with 13% in the FK-treated group. The patients receiving both CsA and OKT3 had a higher rate of upper gastrointestinal CMV infection than did FK-treated patients who also received OKT3 therapy (38.5% versus 20%, respectively). Based upon these data, it can be concluded that (1) patients receiving FK have a lower incidence of enteric CMV infection; (2) following OLTx, upper gastrointestinal CMV infection presents later in FK-treated patients; (3) the stomach is the most frequently involved organ in the UGIT; (4) FK-treated liver recipients have less severe enteric CMV infection than do CsA-treated patients; (5) enteric CMV is not a major cause of mortality in liver transplant recipients; and (6) in patients receiving FK, those who require OKT3 therapy do not appear to be at a greater risk for the development of CMV enteritis than those who do not.

Adolescent↗
PubMed1992

The association of IgA deficiency but not IgG or IgM deficiency with a reduced patient and graft survival following liver transplantation.

Recipients of solid organ allografts require lifelong immunosuppression in order to prevent graft rejection and to maintain graft function. In general, such immunosuppression greatly impairs the cellular immune system, as this level of the immune system is principally responsible for self and non-self recognition. The consequences of allograft transplantation in terms of patient and graft survival when transplants are given to individuals who have a preexisting humoral immune deficiency characterized by a deficiency of the serum levels of one or more of the major Ig classes have not yet been reported. From February 1, 1981 through December 31, 1990, a total of 43 adult patients with a deficiency of 1 or more Ig classes received a ABO-matched liver allograft at this institution. This sample represents 2.5% of a total of 1684 adults transplanted during this interval. These 43 liver graft recipients could be divided into 3 major groups based upon the presence of an IgG, IgM, or IgA deficiency. IgG deficiencies were defined as levels less than 50 mg/dl. Patient and graft survival for the IgA-deficient group was significantly reduced (P less than 0.04 and P less than 0.009, respectively) compared with both the IgG- and IgM-deficient groups. The latter two groups did not differ from controls without an Ig deficiency for these same two endpoints. The major causes of death in the IgA-deficient group were sepsis and opportunistic infection. A third of the deaths in the IgA-deficient group occurred in the perioperative period (first 30 days) while greater than 50% of the deaths occurred within the first 3 months, and all deaths occurred before the first year. Based upon these data, the following conclusions can be made: (1) serum IgA deficiency but not IgG or IgM deficiency is associated with an increased post-OLTx death and graft loss rate; (2) the majority of these deaths are due to sepsis or an opportunistic infection; and (3) most of the deaths occur early. These data suggest that recognition of a deficiency of IgA prior to organ grafting necessitates meticulous attention to the prevention of infection in the immediate perioperative period if patient and graft survival of these patients is to be improved.

Adult↗
PubMed1992

Hepatic artery pseudoaneurysm ligation after orthotopic liver transplantation--a report of 7 cases.

Pseudoaneurysm (PA) is a rare but life-threatening complication of liver transplantation. The authors present their experience on 7 patients treated by ligation of a post-OLT PA. Hepatic artery ligation or embolization was performed from 10 to 70 days after liver transplantation. Of the seven patients, four survived, one developed a biliary stricture, treated by percutaneous balloon dilatation, two died of a complication not related to treatment, and one died of multiple organ failure.

Adult↗
PubMed1992

Ethanol-associated alterations in the kinetics of putrescine uptake and metabolism by the regenerating liver.

Biosynthesis of the polyamines, putrescine, spermidine, and spermine is required for DNA synthesis and liver regeneration after partial hepatectomy. We have previously reported that chronic ethanol consumption impairs polyamine synthesis and significantly retards liver regeneration after partial hepatectomy. In those studies, supplementation with putrescine restored hepatic DNA synthesis in ethanol-fed rats but exerted no effect in pair-fed controls. These differences in the response to putrescine treatment may have resulted from ethanol-associated differences in hepatic uptake, release, or metabolism of putrescine. To resolve these issues and define more completely how putrescine treatment affects DNA synthesis, we now assess the kinetics of putrescine uptake and metabolism after intraperitoneal or intravenous injection of radiolabeled putrescine (1.2 mmol/kg, specific activity 1 microCi/mmol) into rats fed 36% ethanol diets or isocaloric, nonethanol diets for 6 weeks prior to partial hepatectomy. After putrescine treatment, hepatic putrescine concentrations were greater in ethanol-fed rats than controls. Differences in post-treatment hepatic putrescine levels between ethanol and pair-fed groups could not be explained by differences in the rates of hepatic putrescine uptake or excretion into bile; residual de novo synthesis of putrescine from ornithine or metabolism of hepatic putrescine to its polyamine products, spermidine and spermine. Indeed, supplemental putrescine was not appreciably converted to spermidine or spermine in either ethanol or control rats. Hence, these latter polyamines are unlikely to be responsible for the treatment-associated improvement in DNA synthesis that has been noted in ethanol-fed rats. This suggests that putrescine itself acts to restore hepatic DNA synthesis in ethanol-fed rats.

Alcoholism↗
PubMed1991

Changes in cognitive and language functioning of preschool children with autism.

Preschool children with autism and their normally developing peers were compared on the Stanford-Binet IV and Preschool Language Scale before and after 1 school year. Both measures showed that although the children with autism functioned at a lower level than their normally developing peers, the children with autism had narrowed this gap after treatment, making a nearly 19-point increase in IQ and an 8-point gain in language quotient. The IQ measure remained stable for the normally developing peers while their language showed a 7.73-point increase. The data support the notion that young children with autism can make very significant developmental gains.

Autistic Disorder↗
PubMed1991

Interaction of felbamate and diazepam against maximal electroshock seizures and chemoconvulsants in mice.

The anticonvulsant effects of felbamate alone or in combination with diazepam were investigated against maximal electroshock-, pentylenetetrazol-, isoniazid- and bicuculline-induced seizures in mice. A single subprotective dose of felbamate, a dose which offers no protection to animals when combined with diazepam, enhanced the protective effects of diazepam against seizures induced by electroshock, pentylenetetrazol and isoniazid, as measured by significant reduction of ED50 values. However, felbamate failed to significantly affect the protective action of diazepam against bicuculline. Felbamate does not interact directly with the GABA-benzodiazepine-ionophore complex. Thus the enhancement of anticonvulsant activity of diazepam by felbamate against maximal electroshock and pentylenetetrazol may involve an indirect effect at benzodiazepine receptors. The anticonvulsant action of felbamate against isoniazid does not seem to involve benzodiazepine receptors and may be due to reversing the inhibitory effect of isoniazid on glutamate decarboxylase (GAD) activity. The interaction between felbamate and diazepam may also involve other mechanisms.

Animals↗
PubMed1991

The hearing loss associated with exposure to toluene is not caused by a metabolite.

Exposure to toluene causes a marked hearing loss in rats, and this effect has been observed in some human solvent abusers. The issue of whether toluene or one of its metabolites is responsible for this effect has not been examined. To attempt to resolve this issue, we manipulated the metabolism, and thus the circulating levels, of toluene as follows. Two groups of rats were exposed to phenobarbital (PB) in their drinking water (0.1%) for seven days to induce detoxifying liver enzymes; two other groups had access to PB-free water. Then half of the rats exposed to PB or water were exposed to filtered air or a concentration of toluene expected to cause hearing loss. Levels of toluene in blood were markedly reduced by the PB and the excretion of hippuric acid was increased. All rats were tested for auditory sensitivity by brainstem auditory-evoked response (BAER) audiometry using a 16-kHz tone pip. The rats exposed to toluene alone showed a marked reduction in the integrated BAER waveform, indicative of the expected hearing deficit. None of the other treated rats showed any deviation from controls (i.e., water and air). These results provide strong evidence that toluene itself is responsible for the auditory dysfunction. Toluene also caused the rats to increase their fluid consumption and urine output; these effects were not altered by PB. Identification of toluene as the proximal ototoxicant should facilitate the search for the mechanism of this effect.

Acoustic Stimulation↗
PubMed1991

Does the presence of a measurable blood alcohol level in a potential organ donor affect the outcome of liver transplantation?

The widespread application of hepatic transplantation has created a tremendous demand for donor organs. An assessment of donor parameters is thought to be important in selecting good donors; however, the criteria utilized have not been standardized. This study was performed to determine the effect of a measurable donor blood alcohol level on graft survival. Fifty-two patients who underwent orthotopic liver transplantation at the University of Pittsburgh were included in the study. Twenty-five patients received liver grafts from donors having a blood alcohol level between 0.04 and 0.4 g/l with a mean of 0.17 g/l. Twenty-seven patients received a liver graft from a donor who had no measurable blood alcohol. There were no differences between these two groups of donors regarding the time of initial hospitalization until the time of donation. Graft failure within the first 30 days was 24% for those receiving an organ from an alcohol-positive donor as compared with 22.2% in those receiving an organ from an alcohol negative donor. The recipient mortality rate was 16% and 11%, respectively. No relationships between the donor blood alcohol level and organ performance, frequency of primary graft nonfunction, or number of episodes of acute cellular rejection were evident. Based upon these data, the presence of a measurable blood alcohol level in a donor should not mitigate against organ donation.

Adult↗
PubMed1991

Variability in growth of Neisseria polysaccharea on colistin-containing selective media for Neisseria spp.

In a prospective survey of 773 healthy schoolchildren in southern Alberta, Canada, Neisseria polysaccharea was isolated from the pharynxes of only 4 (0.5%) subjects, whereas Neisseria lactamica and Neisseria meningitidis were isolated from 110 (14%) and 15 (2%) children, respectively. These strains of N. polysaccharea, together with three other sporadic isolates from Alberta, Canada, were compared with the type strain from France and strains from Spain and Germany. All strains were phenotypically identical, except that the Canadian and German strains, for which the colistin MICs were 1 mg/liter, failed to grow on Thayer-Martin medium (TMM), whereas the type strain and the Spanish strains, for which the colistin MICs were greater than 7.5 mg/liter, were not inhibited. Multilocus enzyme electrophoresis indicated that six distinct electrophoretic types were present among the seven Canadian strains. Our results show that growth on gonococcal selective media which contain colistin is a variable feature of this taxon.

Adolescent↗
PubMed1991

One hundred ten consecutive primary orthotopic liver transplants under FK 506 in adults.

An account is given of the 6- to 12-month survival, and causes of failure in 110 consecutive patients who underwent primary liver transplantation under treatment from the outset with FK 506 and steroids. The patient survival is 92.7%, and the first graft survival is 87.3%. At a very high frequency, the patients achieved good graft function, and they had a relatively low morbidity that was partially ascribable to minimal use and early discontinuance (in 60% of cases) of steroids. Renal dysfunction and other adverse findings were largely confined to patients with poor initial graft function and consequent apparent alteration of the kinetics of FK 506 elimination, causing functional overdosage. Results compare very favorably with our past record using conventional immunosuppression, and support the belief that FK 506 is a superior immunosuppressive agent which is suitable for chronic administration.

Adult↗