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Biomedical subjects

J Hester

Publications and source records attributed to J Hester.

53 records · Page 3Linked to original sources
PubMed1989

Decreased arterial wall prostaglandin production in neonatal calves with severe chronic pulmonary hypertension.

Neonatal calves exposed to chronic hypobaric hypoxia develop severe pulmonary hypertension associated with altered vascular reactivity, cellular proliferation, and increased elastin and collagen production. We hypothesized that prostaglandin (PG) production would be decreased in the pulmonary arterial vessel wall of these calves. Further, because of the possibility that the hemodynamic stresses of hypoxic pulmonary hypertension might change along the longitudinal axis of the pulmonary circulation, we measured prostaglandin synthetic capability in tissues isolated from proximal pulmonary artery, distal pulmonary artery, and pulmonary vein. We found that PGI2 production was decreased in both proximal and distal pulmonary artery rings isolated from pulmonary hypertensive calves compared to controls. PGI2 production was greater in distal than in proximal lobar pulmonary artery. In contrast, pulmonary veins from hypertensive calves, which are protected from the hemodynamic stress of pulmonary arterial hypertension, did not demonstrate altered PGI2 production compared to controls. PGE2 production was also decreased in proximal hypertensive pulmonary arterial rings as compared to controls. To determine if this decrease in vessel wall production of prostaglandins was due to changes in cellular prostaglandin production, we studied prostaglandin production by the three major cell types comprising hypertensive and control arteries. Endothelial cells cultured from hypertensive main pulmonary artery produced less PGI2 than did those from control artery, and there appeared to be a shift from PGI2 production to PGE2 production in endothelial cells isolated from hypertensive artery. Explanted advential fibroblasts from hypertensive artery produced less PGE2 than did controls. Smooth muscle cell PGI2 production did not differ between cells isolated from hypertensive and control arteries in these brief 30-min incubations. We conclude that there is a relative deficit in PGI2 and PGE2 production in the pulmonary arteries of calves with hypoxia-induced pulmonary hypertension and speculate that this contributes to altered vascular tone and vessel remodeling.

Animals↗
PubMed1988

Patient choice of providers in a preferred provider organization.

This article is an analysis of patient choice of providers by the employees of the Security Pacific Bank of California and their dependents who have access to the Med Network Preferred Provider Organization (PPO). The empirical results show that not only is the PPO used by individuals who require relatively little medical care (as measured by predicted office visit charges) but that the PPO is most intensively used for low-risk services such as treatment for minor illness and preventive care. Also, the most likely Security Pacific Health Care beneficiary to use a PPO provider is a recently hired employee who lives in the south urban region, has a relatively low income, does not have supplemental insurance coverage, and is without previous attachments to non-PPO primary care providers. In order to maximize their ability to reduce plan paid benefits, insurers who contract with PPOs should focus on increasing PPO utilization among poorer health risks.

Adolescent↗
PubMed1988

Multiple agent chemotherapy (POACH) in previously treated and untreated patients with chronic lymphocytic leukemia.

A multiple agent chemotherapy protocol utilizing cyclophosphamide, adriamycin, cytosine-arabinoside, vincristine, and prednisone (POACH) was administered to 65 patients with chronic lymphocytic leukemia. Nineteen (56%) of the 34 previously untreated patients responded, with (21%) of the patients obtaining a complete remission. The response rate for the 31 previously treated patients was significantly lower, with 2 complete remissions and 6 partial remissions. The median survival of the untreated patients was 58 months, compared with 15 months for the previously treated group (p less than 0.01). In both groups, patients who achieved a complete or partial remission had a significantly longer survival than did patients who did not respond. The response rates for all sites of involvement were similar. Sixteen (47%) of 34 previously untreated patients and 9 of 31 (29%) previously treated patients returned to Rai stage 0. The survival of patients who returned to stage 0 was significantly superior to that of others in both groups. The overall mortality during the study was significantly higher for previously treated patients. Pretreatment Rai stage was strongly predictive of death on study. Rai and Binet stages were not strongly predictive of response or length of survival in untreated patients but stages were predictive for survival and in treated patients. The regimen was well tolerated, with infectious complications being the major morbidity. Patients who responded to POACH had a significantly longer survival than did those who did not, and further attempts to improve the complete and partial remission rates in chronic lymphocytic leukemia will be undertaken.

Adult↗
PubMed1987

High dose cyclophosphamide, BCNU, and VP-16 (CBV) as a conditioning regimen for allogeneic bone marrow transplantation for patients with acute leukemia.

A high dose combination chemotherapy regimen (CBV) consisting of cyclophosphamide (1.5 gm/m2 day 1 to day 4); BCNU (300 mg/m2 day 1) and etoposide (100 mg/m2 every 12 hours for 6 doses), followed by bone marrow transplant from human leukocyte antigen (HLA) identical sibling donors, was evaluated in 29 patients in whom acute leukemia was in relapse or remission. Engraftment of donor cell type occurred in all but one of 21 patients, in whom marker differences between donor and recipient were established. Two of 11 patients transplanted during relapse of the disease, lived beyond 1 year after bone marrow transplantation. One patient died free of leukemia, 41 months after transplantation of meningitis. Two of seven patients transplanted during the second remission of the disease, are alive and free of leukemia at 42+, and 8+ months. All patients transplanted during the third or fourth remission of the disease have died from either a further relapse, or transplant related causes. The low incidence of organ toxicity with CBV allows for further dose escalation of its drug components.

Acute Disease↗
PubMed1986

C-sis and C-abl expression in chronic myelogenous leukemia and other hematologic malignancies.

Cellular oncogenes have been localized at the breakpoints of characteristic chromosomal rearrangements occurring in certain hematologic malignancies. This has been reported to result in aberrant expression of the involved oncogenes. Over 90% of chronic myelogenous leukemia (CML) is characterized by a reciprocal translocation that brings c-abl from chromosome 9 to chromosome 22, and c-sis from chromosome 22 to chromosome 9. To investigate the possible role of these two oncogenes in the leukemic process, we studied their expression in a number of fresh samples obtained from patients with various forms of leukemia, by Northern blot analysis using c-onc probes. Seven of 24 samples obtained from patients with either CML or chronic myelomonocytic leukemia expressed a normal 4.0-kilobase (kb) c-sis transcript. C-sis expression was found only in the accelerated/blast phases but not in the chronic phase of CML. All of the CML Philadelphia chromosome-positive (Ph1+) samples expressed an aberrant 8-kb c-abl transcript. The expression of c-sis in

Humans↗
PubMed1985

Allogeneic bone marrow transplantation for acute leukemia refractory to induction chemotherapy.

This article compares the outcome of 14 patients with primary refractory acute leukemia who underwent bone marrow transplantation from human leukocyte antigen (HLA)-identical donors with that of 18 age-matched control patients who received chemotherapy. Complete clearing of leukemia was seen in all 14 transplanted patients. Five of the transplanted patients are alive 98 to 1790 days posttransplant, and four are free of leukemia. Nine patients have died, eight with severe graft-versus-host disease associated with interstitial pneumonia or systemic infections and one with relapse from chemotherapy-associated infections. Engraftment was seen in all patients. Severe graft-versus-host disease (grades III and IV) was seen in ten patients and resolved in three patients following high-dose corticosteroid treatment. Three of the 18 control patients are alive, none of them in complete remission. It appears that the combination of piperazinedione and total-body irradiation followed by allogeneic transplant is effective induction treatment for primary refractory acute leukemia and will be considered in the future as first salvage treatment for patients failing induction treatment.

Acute Disease↗
PubMed1985

Intensive combination chemotherapy (ROAP 10) and splenectomy in the management of chronic myelogenous leukemia.

To investigate the role of intensive chemotherapy in chronic myelogenous leukemia (CML), we treated 37 patients who had Philadelphia-positive benign-phase disease with rubidazone 300 mg/m2/d 1 (or daunorubicin 30 mg/m2/d X 4), cytosine arabinoside 80 mg/m2/d X 10, vincristine 2 mg/d 1, and prednisone 100 mg/d X 5 (ROAP 10), every four weeks for a median of three cycles. This treatment was followed by splenectomy and by subsequent maintenance therapy with 1 to 5 g hydroxyurea daily in intermittent courses. After a median follow-up of 42 months (range, 24 to 54 months), 20 patients (54%) remain in benign phase. The projected median survival is 52 months, and the three-year survival rate is 67%. Six patients (16%) developed blastic crisis, and eight died in the benign phase. A significant cytogenetic response, defined as a fall in the percentage of Philadelphia-positive cells to less than or equal to 30%, occurred in 18 (53%) of 34 patients who had serial cytogenetic studies. Six patients (18%) had reductions to 35% to 90%, whereas ten remained 100% positive. Cytogenetic response lasted for a median of six months from the time of maximal response (range, 1 to 18 months). Blastic crisis or accelerated disease developed in seven (44%) of the 16 patients who manifested minimal or no cytogenetic response, compared to only two of the 18 patients (11%) who achieved a significant cytogenetic response. Toxicity, which resulted in one death, was due to myelosuppression and consisted of febrile episodes during neutropenia (24% of courses), documented infections (8% of courses), and bleeding (8% of courses). ROAP 10 intensive therapy produces moderate survival improvement for CML patients compared to a matched historical control group of patients treated at our institution, but it has considerable myelosuppressive toxicity. The Philadelphia chromosome response is an important treatment-related prognostic factor.

Adolescent↗
PubMed1983

Clinical course and response to treatment of patients with acute myelogenous leukemia presenting with a high leukocyte count.

The natural history and response to treatment of 46 patients with acute myelogenous leukemia and a pretreatment leukocyte count of 100,000/microliters or higher were reviewed to identify the clinical features and response characteristics to the treatment of this group of patients. While the response rate of 52% was similar to that of patients with lower leukocyte counts, remission durations were shorter and related inversely to the height of the initial leukocyte count and to the number of treatment courses necessary to achieve a complete remission. A high incidence of hemorrhagic deaths was observed during the first 8 days of treatment. These hemorrhages occurred at a time when the leukocyte count was falling secondary to chemotherapy and the platelet count was still greater than 15,000/microliters. Pretreatment coagulation disorders and poor performance status were factors associated with this fatal complication. Antimetabolites to rapidly arrest leukemic cell proliferation and leukapheresis to avoid further leukostatic plug formation may be useful immediate measures to reduce the incidence of these fatal hemorrhages until the underlying pathogenic mechanisms have been elucidated.

Adult↗
PubMed1979

Autologous bone-marrow transplantation in relapsed adult acute leukaemia.

24 cases of adult acute leukaemia, of which 21 were evaluable, were treated in irreversible relapse with high-dose piperazinedione and supralethal total-body irradiation (T.B.I.) in conjunction with autologous marrow transplantation (A.B.M.T.). The grafted marrow cells had been collected and stored in liquid nitrogen at the time of remission. In 12 patients the marrow cells were fractionated on discontinuous albumin gradients in an attempt to separate normal cells from residual leukaemic cells. 11 patients achieved complete remission (C.R.); 7 other patients had signs of engraftment but died before C.R. The median remission duration was 4 months (2-14). 6 of 9 acute myeloblastic leukaemia patients, in whom bone-marrow transplantation was the first treatment of relapse, achieved C.R. 4 of 5 patients with acute lymphoblastic leukaemia, whose bone-marrow cells were collected during first remission, reached C.R. Autologous bone-marrow transplantation is a valuable first treatment for acute myeloblastic leukaemia in relapse and acute lymphoblastic leukaemia in second relapse.

Adolescent↗
PubMed1979

Effects of time, platelet concentration, and sex on the human platelet aggregation response.

The platelet aggregation responses induced by adenosine diphosphate (ADP) and collagen were characterized by parameters defining rate and extent of reaction. Values were compared on the basis of platelet concentration, time elapsed between sample collection and test performance, and sex of donors. Rate and extent of aggregation varied as a function of platelet concentration. Maximal responses were obtained for platelet concentrations greater than 100,000/microliter. Results from samples processed after 90 min of incubation at room temperature were consistently and significantly lower than those obtained from samples processed immediately. ADP-induced aggregation responses elicited by samples from male and female normal donors differed significantly. This indicates that comparisons between normal and patient results should be made with sex-matched individuals to avoid erroneous interpretations.

Adenosine Diphosphate↗
PubMedDate not supplied

Remember the gum-elastic bougie at extubation.

Although the use of a gum-elastic bougie to secure an airway is well described, its use during extubation is not well documented. A bougie was passed through the endotracheal tube (ETT) prior to extubation in anticipation of possible reintubation of a patient with a difficult airway. Once the bougie was in place, the ETT was removed over it. Later, when the patient's airway did become compromised, the trachea was rapidly reintubated using the bougie, without the need for direct laryngoscopy, fiberoptic bronchoscopy, or, worse, emergency tracheostomy.

Adult↗