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Biomedical subjects

P B Gregory

Publications and source records attributed to P B Gregory.

At least 37 records · Page 2Linked to original sources

Antiviral treatment of chronic hepatitis B virus infection: pharmacokinetics and side effects of interferon and adenine arabinoside alone and in combination.

In an uncontrolled trial, 29 patients with chronic hepatitis B virus infection were treated with 93 courses of adenine arabinoside at doses ranging from 2.5 to 15 mg/kg per day. Most patients were treated concomitantly with human leukocyte interferon. Significant, but transient, neurotoxicity was seen with adenine arabinoside therapy in 44% of all courses. Manifestations of toxicity were mainly neurological and ranged from pain syndromes to tremors and, rarely, seizures. Suppression of numbers of lymphocytes was also noted. All effects were reversible with time. The extent of toxicity was dependent upon the dosage of adenine arabinoside. Treatment with interferon appeared to potentiate the occurrence of toxicity with adenine arabinoside. Arabinofuranosylhypoxanthine serum levels increased in a dose-dependent manner and tended to accumulate in interferon-treated hepatitis patients during a course of therapy. Elevated blood levels and drug accumulation were associated with toxicity in a significant fashion. Human leukocyte interferon was administered to 38 patients in 113 separate courses. Interferon side effects were rapidly reversible upon cessation of therapy. These included initial fever, myalgias, and hair loss as well as suppression of granulocytes, platelets, and lymphocytes in the blood.

Drug Therapy, Combination↗

Continuous intravenous vasopressin in active upper gastrointestinal bleeding.

Sixty patients with active upper gastrointestinal bleeding were randomized to received either continuous intravenous infusions of vasopressin (29 patients) or placebo (31 patients) at a rate of 40 U/h. Six hours after beginning the study, 13 patients in the vasopressin group and 11 in the placebo group] had ceased bleeding (p = 0.46). By 24 hours. 17 patients in the vasopressin group and 14 in the placebo group had stopped bleeding (p = 0.30). Restriction of the analysis to patients bleeding from varices showed no advantage with vasopressin treatment after 6 or 24 hours. No consistent trend favoring use of vasopressin to stop hemorrhage was noted during the 30-month study period. There was little difference between the two groups in the number of patients needing surgery (13 on vasopressin, 18 on placebo; p = 0.30) or the number of deaths (eight on vasopressin, 11 on placebo; p = 0.51); the transfusion requirement was the same. In our patients, a continuous intravenous infusion of vasopressin neither controlled bleeding nor altered outcome.

Clinical Trials as Topic↗

Antiviral treatment of chronic hepatitis B virus infection. I. Changes in viral markers with interferon combined with adenine arabinoside.

Twenty patients with chronic active hepatitis and 12 patients with chronic persistent hepatitis associated with hepatitis B virus (HBV) infection were treated with human leukocyte interferon or adenine arabinoside alone or in combination. With interferon alone, four of 16 patients showed a permanent disappearance of HBV-associated DNA polymerase (DNAP) activity from serum. Of six patients treated with adenine arabinoside alone, only one patient became permanently DNAP-negative. With a regimen of multiple cycles of combined interferon and adenine arabinoside, seven of 16 male patients became permanently DNAP-negative. Of 69 patients who met the criteria for admission to the program, spontaneous decreases in DNAP activity without treatment were observed in only 9% during a mean observation period of 10 months. In general, patients with chronic active hepatitis, those who are female, and those with a history of recent steroid therapy responded to the antiviral agents significantly better than did the other patients.

Adult↗

Diuresis in the ascitic patient: a randomized controlled trial of three regimens.

To compare the efficacy of three commonly used diuretic regimens in the treatment of ascites, we randomized 90 patients to three treatment groups: Sequential Spironolactone (spironolactone followed by furosemide if necessary), Combination (spironolactone and furosemide in combination), and Furosemide (furosemide given alone). Diuretics were begun at a low dose by mouth and the dosage increased until a 0.4-0.8 kg daily diuresis was achieved. The clinical and laboratory findings were comparable for the three experimental groups on admission to the study. All three regimens achieved a comparable rate of diuresis. To do so was far more difficult with furosemide alone, which required repetitious upward adjustments in dosage and massive KCl supplements. The incidence of encephalopathy, hepatorenal syndrome, and marked electrolyte abnormalities was similar for the three treatment groups except that severe hyperkalemia was more frequent on combination therapy. We conclude that diuresis should be initiated with one of the two spironolactone regimens and not with furosemide as the sole agent.

Ascites↗

Bleeding after liver biopsy.

During nine years 3,080 liver biopsies were carried out and bleeding occurred in 22 of the patients (0.7 percent). Transfusions were given to 17 of these patients and laparotomies were done to control the bleeding in six. All survived. Bleeding was evident within three hours in 19 patients, but occurred from 3 to 13 days after biopsy in the remaining three. Pain requiring analgesic medication and a fall in blood pressure were the usual indications that major bleeding had occurred. Relative contraindications to biopsy (particularly a prolonged prothrombin time) were present in 10 of the 22 bleeding patients and in only 2 of the 41 nonbleeding controls (P<0.001). We believe that some of the bleeding episodes could have been prevented with more careful attention to the indications and contraindications to biopsy, and more rigorous correction of recognized clotting abnormalities.

Biopsy, Needle↗

Furosemide disposition in cirrhotic patients.

Furosemide disposition in 7 cirrhotic subjects and 4 age-matched healthy controls was studied to determine the contribution of differences in pharmacokinetics to the decreased responsiveness observed in cirrhotics. Subjects were given 80 mg of furosemide orally and intravenously on separate occasions, and plasma and urine samples were collected and analyzed for furosemide by high performance liquid chromatography. The half-life of furosemide was 74% greater in the cirrhotic subjects, the result of a smaller increase in volume of distribution (30%) and a decrease in total plasma clearance (15%). The change in plasma clearance was due entirely to a change in nonrenal clearance, since renal clearance was very similar in both groups. The fraction of furosemide not bound to plasma proteins increased by 48%. Furosemide bioavailability was the same in cirrhotic subjects and controls. Consistent with other reports, there was considerable intersubject variability in all of the measured and computed parameters. The results show that differences in disposition play little, if any, role in the decreased renal responsiveness to furosemide.

Administration, Oral↗

Effects of immunosuppressive therapy on viral markers in chronic active hepatitis B.

Hepatitis B virus associated DNA polymerase activity, hepatitis b surface antigen (HBsAg), and serum aspartate aminotransferase were followed in 21 patients with chronic active hepatitis while immunosuppressive therapy (prednisone +/- azathioprine) was being withdrawn. In every case, DNA polymerase activity fell within 6-10 wk of decreasing treatment and became undetectable in 8 patients. This was usually accompanied by a fall in HbsAg titer and a transient rise in serum aspartate aminotransferase activity. Four additional patients with previously untreated HbsAg positive chronic active hepatitis were placed on prednisone for 12 wk. There was a rise in DNA polymerase activity and HBsAg titer with a fall in serum aspartate aminotransferase values during treatment. Upon discontinuing therapy, DNa polymerase activity fell dramatically in all 3 patients who completed their course of prednisone and became undetectable in 1. These findings suggest that immunosuppressive therapy has a potentiating effect on hepatitis B viral replication in patients with chronic active hepatitis.

Adult↗

Enhanced bioavailability and decreased clearance of analgesics in patients with cirrhosis.

The effect of moderate cirrhosis on the bioavailability and systemic clearance of three model analgesic compounds (pethidine, pentazocine, and salicylamide) with substantial first-pass metabolism was examined in 8 cirrhotic subjects and 4 agematched healthy controls. There was a 46% decrease in the clearance of pentazocine and a 278% increase in bioavailability. The corresponding figures for pethidine were 36% and 81%. The area under the plasma curve after oral salicylamide was increased by 551% in cirrhotic subjects compared with controls. This study demonstrated that drugs with the highest hepatic clearance will have the largest relative increases in bioavailability in cirrhotic patients due to portosystemic shunting. The decrease in clearance and increase in bioavailability will have multiplicative, rather than simply additive, effects on total area under the curve and, if related, pharmacologic response.

Adult↗

Complications of diuresis in the alcoholic patient with ascites: a controlled trial.

Forty-three patients with decompensated alcoholic liver disease and ascites of recent onset were randomized to salt and water restriction alone (control group) or to salt and water restriction plus diuretics (diuresis group). The two treatment groups were comparable in clinical findings and laboratory results. Seven patients in the control group and 5 patients in the diuresis group died during the acute illness. Weight loss was more marked and the disappearance of ascites more common in those given diuretics. A modest decrease in serum sodium and increase in serum potassium, and readily reversible elevations of blood urea nitrogen were noted in the diuresis group. Eight patients in each treatment group developed either the hepatorenal syndrome, marked electrolyte abnormalities, or encephalopathy. Diuresis can be accomplished in these critically ill patients without serious complications that can be attributed to the diuretic treatment.

Alcoholism↗