PubMed Health⌕ Search

Biomedical subjects

C Long

Publications and source records attributed to C Long.

At least 73 records · Page 4Linked to original sources
PubMed1993

Detection of latent variegate porphyria by fluorescence emission spectroscopy of plasma.

The plasma of patients with overt variegate porphyria contains porphyrin with a fluorescence emission maximum at about 626 nm, which is diagnostic for the condition. We have evaluated qualitative fluorescence emission scanning of saline-diluted plasma as a method for the identification of asymptomatic carriers of the gene for variegate porphyria. Plasma from 36 unrelated patients with variegate porphyria, 136 of their asymptomatic first- and second-degree relatives aged 15 years or over, and 322 normal subjects was scanned. An emission maximum between 621 and 627 nm was observed in the 36 patients with variegate porphyria and 54 of their relatives, but not in any normal subject, nor in 56 patients with other types of porphyria. For the detection of asymptomatic adult carriers of the gene for variegate porphyria, fluorescence emission scanning of plasma appears to be 100% specific, with a sensitivity of 86% (95% confidence interval 71-98%). In contrast, the sensitivity of faecal porphyrin analysis as a test for adult gene carriers was 36%. These results suggest that fluorescence emission scanning of plasma should replace faecal porphyrin analysis as the test of first choice for this purpose.

Adolescent↗
PubMed1992

Field trial of rhesus rotavirus or human-rhesus rotavirus reassortant vaccine of VP7 serotype 3 or 1 specificity in infants. The Elmwood, Panorama, and Westfall Pediatric Groups.

Orally administered live rhesus monkey rotavirus vaccine (RRV, VP7 serotype 3) and human-rhesus reassortant rotavirus vaccine (DxRRV, VP7 serotype 1) were evaluated in a placebo-controlled field trial of 223 infants 2-4 months old. Both vaccines were mildly reactogenic but were generally well tolerated in the 10 days after vaccination. RRV and DxRRV were immunogenic, inducing serum antibody responses in 78% and 71% of the vaccines, respectively. Efficacy of RRV vaccine was 66% (P = .01) and of DxRRV vaccine 77% (P = .002) against rotavirus-associated illness in the first season after vaccination. Efficacy of RRV vaccine against rotavirus-associated illness over three rotavirus seasons was 51.2% (P = .045) and of DxRRV vaccine was 67.3% (P = .006). RRV vaccine provided heterotypic protection of 58.5% (P = .041) and DxRRV vaccine provided homotypic protection of 72.8% (P = .005) over three seasons against the predominant serotype 1 rotavirus.

Administration, Oral↗
PubMed1991

Renal interstitial hydrostatic pressure and PGE2 in pressure natriuresis.

The present study tested the hypothesis that the presence of renal prostaglandin E2 (PGE2) is necessary for full natriuretic response to increased renal interstitial hydrostatic pressure (RIHP) during increased renal perfusion pressure (RPP). In control untreated pentobarbital-anesthetized dogs (n = 7), fractional excretion of sodium (FENa) was 1.17 +/- 0.48, 1.07 +/- 0.24, and 2.69 +/- 0.57% at RPP of 90, 122, and 148 mmHg, respectively. These changes in FENa were associated with effective renal blood flows (ERBF) of 1.43 +/- 0.20, 1.49 +/- 0.23, and 1.99 +/- 0.40 ml.min-1.g kidney wt-1, respectively. Similarly, glomerular filtration rate (GFR) was 0.53 +/- 0.10, 0.71 +/- 0.10, and 0.72 +/- 0.14 ml.min-1.g kidney wt-1, respectively. Treatment with indomethacin, a cyclooxygenase inhibitor, significantly lowered FENa to 0.45 +/- 0.13, 0.77 +/- 0.21, and 1.19 +/- 0.59% at RPP of 91, 121, and 146 mmHg, respectively. Additionally, indomethacin treatment lowered ERBF (0.51 +/- 0.15, 0.52 +/- 0.10, and 0.85 +/- 0.21 ml.min-1.g kidney wt-1) and GFR (0.28 +/- 0.09, 0.34 +/- 0.09, and 0.47 +/- 0.09 ml.min-1.g kidney wt-1) at low, middle, and high RPP, respectively. PGE2 replacement (n = 6) into renal artery at 0.01 microgram.min-1.kg body wt-1 returned FENa, ERBF, and GFR to control levels over the same range of RPP, whereas prostacyclin (PGI2) infusion (n = 7) at the same dose did not. RIHP was 4.2 +/- 1.2, 4.2 + 0.5, and 7.5 +/- 1.7 mmHg with increasing RPP in control untreated group and increased to similar levels with indomethacin treatment and during PGE2 or PGI2 replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Tort reform and the obstetric access crisis. The case of the WAMI states.

The states of Washington, Alaska, Montana, and Idaho (WAMI) have all had declines in the proportion of physicians offering obstetric services during the past few years, a decline precipitated by rising medical malpractice premiums. One response to the problem of rising liability premiums has been the passage of extensive tort reform legislation. We present the results of recent studies of physicians' obstetric practices in the WAMI states and summarize the major changes in tort legislation and regulation that have occurred in these states. Most general and family physicians in the WAMI region no longer provide obstetric care; by contrast, more than 80% of the obstetrician-gynecologists in the WAMI states are still practicing obstetrics. Despite the fact that only a minority of family physicians are still active in obstetrics, most rural family physicians in all four states still deliver babies. Most physicians in all four states limit the amount of care they provide to those covered by Medicaid, which suggests that significant barriers to care exist for medically indigent persons. All four states have adopted significant tort reforms. Despite these changes in the legal environment, the cost of malpractice premiums and concerns over the likelihood of being sued continue to limit the number of physicians willing to provide obstetric care. Although it cannot be inferred from these data that tort reform has decreased the rate at which physicians give up obstetric practice, the evidence is compatible with such a conclusion.

Alaska↗
PubMed1990

Cerebrovasculr response to CO2 in edematous brain during either fentanyl or isoflurane anesthesia.

Cerebral blood flow response to changes in PaCO2 was studied in the edematous cerebral cortex of 19 patients with malignant supratentorial tumors using laser Doppler flowmetry technology. General anesthesia for craniotomy was induced with thiopental, 3-5 mg/kg i.v., and N2O, 60% in O2. In random sequence, 8 patients were assigned to receive fentanyl, 6 +/- 1.6 (SEM). mug/kg i.v.; the other 11 received isoflurane, 0.56% end-tidal + 0.07 (SEM). After a craniotomy bone flap was turned and the dura was opened, laser flowmetry probes were placed over surgically undisturbed cortex that was known to be edematous from preoperative CT and MRI scans. Flow index measurements were first made at hypocarbia (PaCO2 = 24.2 +/- 0.9 and 21.5 +/- 2.1 mm Hg for the fentanyl and isoflurane groups, respectively). Minute ventilation was then decreased and cortical flow index was remeasured with PaCO2 = 34.2 +/- 0.6 and 33.0 +/- 0.8 mm Hg for the fentanyl and isoflurane groups, respectively. Hypocarbia during fentanyl-supplemented N2O-O2 anesthesia resulted in a cortical flow index that was 70 +/- 8% of the flow index at near normocarbia (p <0.05). During isoflurane N2O-O2 anesthesia, however, there was a wide variety of responses to hypocarbia, including three patients whose flow indices increased markedly. The mean flow index during hypocarbia was significantly (p <0.05) lower during fentanyl-N2O anesthesia than it was during isoflurane-N2O anesthesia. There was no predictable relationship between the type of brain tumor and the CBF response to hypocapnia during isoflurane-N2O anesthesia. It is concluded that, in edematous brain, cerebral cortical blood flow response to hypocarbia is more likely to be preserved during fentanyl-supplemented N2O-O2 anesthesia than it is during isoflurane-supplemented N2O-O2 anesthesia. In neuropathologic states where hyperventilation is thought to be necessary to reduce cerebral blood flow and decrease brain bulk, isoflurane may be less satisfactory than fentanyl as a supplement to N2O-O2 anesthesia.

Journal Article↗
PubMed1990

Enalapril in the long-term treatment of elderly hypertensives.

The long-term antihypertensive effects of enalapril were assessed for a period of up to 1 year in 44 elderly patients with mild-to-moderate essential hypertension. Following a 2-week placebo period, patients who were assigned to enalapril were followed for 6 weeks in a randomized clinical trial. In patients who benefited from enalapril, treatment was continued and subjects were followed for up to 1 year. Supine and standing systolic and diastolic blood pressures were significantly reduced throughout the 1-year period compared with baseline. The dosage of enalapril was increased from 10 to 20 mg daily in 12 patients; 8 required additional antihypertensive agents. Enalapril is effective in the long-term treatment of hypertension; no loss of antihypertensive agents. Enalapril is effective in the long-term treatment of hypertension; no loss of antihypertensive effect occurs.

Aged↗
PubMed1989

Immunomodulatory and therapeutic properties of FK-565 in mice.

The heptanoyl tripeptide, FK-565 is a biological response modifier with potent therapeutic properties for the treatment of experimental and spontaneous metastases. Doses of FK-565 greater than 5 mg/kg are required for in vivo augmentation of natural killer cells, macrophages, and for therapeutic activity, presumably because FK-565 is a peptide small molecular mass which is rapidly degraded and excreted. Optimal therapeutic activity is observed at approximately 25-50 mg/kg FK-565, administered i.v. three times per week for 4 weeks. In addition to its therapeutic properties, which were consistently greater than the positive control at optimal doses, FK-565 had significant immunoaugmentary properties for natural killer cells, macrophages, and T cells both in vitro and in vivo, suggesting that its therapeutic activity is due to immune augmentation.

Adjuvants, Immunologic↗
PubMed1989

New high O2 carrying perfluorochemical emulsions: toxicity, radiosensitivity of GM-CFC and development of metastases in mice.

The effects of two new concentrated perfluorochemical emulsions based on F-66E and PFOB, which carry significantly more oxygen than Fluosol-DA 20%, were tested on normal tissues (toxicity and radiation response) and on the development of metastases from Lewis Lung Carcinoma (3LL) in female C57 BL/6 mice. Twenty one days after injection of F-66E or PFOB emulsions (15 ml/kg body weight), the spleen and liver weights were significantly increased but had returned to normal after 2-3 months. Splenomegaly already observed in 3LL bearing mice was significantly increased by F-66E emulsion injection. The radiosensitivity of GM-CFC was not altered when unanesthetized GM-CFC was not altered when unanesthetized mice were pretreated with F-66E emulsions and/or carbogen 1 hr prior to and during irradiation. The rate of tumor take and the period before detection of tumors were not modified when an emulsion of F-66E was injected simultaneously or 10 days after 3LL cells. Mean survival of mice, and the number of metastases on lung surfaces were similar in F-66E injected mice and control mice.

Animals↗
PubMed1989

Sufentanil, alfentanil, and fentanyl: impact on cerebrospinal fluid pressure in patients with brain tumors.

In order to evaluate the safety of the new synthetic opioids, alfentanil and sufentanil, in neurosurgical patients, we administered sufentanil 1 microg/kg i.v., alfentanil 50 microg/kg i.v. followed by an infusion of 1 microg/kg/min, or fentanyl 5 microg/kg i.v. to 30 patients with supratentorial tumors anesthetized with nitrous oxide (N2O), 60% in O2. Lumbar cerebrospinal fluid pressure (CSFP) and mean arterial pressure (MAP) responses were recorded for 10 min thereafter, while ventilation was held constant [mean PaCO2 = 36.1 +/- 1.0 mm Hg (SEM)]. There was no change in CSFP after fentanyl. In contrast, both sufentanil and alfentanil caused increases in CSFP, equal to 89 +/- 31 % SE (p < 0.05) and 22 +/- 5% (p < 0.05), respectively. MAP decreased after administration of each opioid. Peak decreases in cerebral perfusion pressure (MAP - CSFP) were 14 +/- 3% after fentanyl, 25 +/- 5% after sufentanil, and 37 +/- 3% after alfentanil. It is concluded that because sufentanil increased CSFP in patients who have brain tumors, it also may be contraindicated in other neurosurgical patients at risk for intracranial hypertension. Alfentanil may share this propensity, since CSFP increased despite a profound reduction in MAP. Among the three opioids evaluated, only fentanyl appears to be appropriate for supplementing N2O-2 anesthesia in patients who have compromised intracranial compliance.

Journal Article↗
PubMed1988

Phantom angina.

Explore the source record for details and available documents.

Angina Pectoris↗