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Biomedical subjects

R J Wong

Publications and source records attributed to R J Wong.

16 recordsLinked to original sources
PubMed1991

Fetal hemoglobin of transfused neonates and spectrophotometric measurements of oxyhemoglobin and carboxyhemoglobin.

The records of 32 neonates in an intensive care unit were examined retrospectively to determine if fetal hemoglobin concentrations could be predicted on the basis of gestational or postnatal age, or on the volume of red blood cell transfusions. In nontransfused neonates, the correlation between measured concentrations of fetal hemoglobin and post-natal age was r = 0.53 with a 17.2 standard error of prediction. In these same neonates, the correlation between measured fetal hemoglobin divided by birth weight and gestational age was r = 0.70, with a 9.6 standard error of prediction. A three-variable regression equation (the latter two variables plus calculated fetal hemoglobin) was found to have a high correlation with data for measured fetal hemoglobin (r = 0.97) and a relatively low 8.4 standard error of prediction. In transfused neonates, however, measured hemoglobin concentrations divided by birth weight correlated poorly with gestational age (r = 0.30 and a 12.4 standard error of prediction). In addition, the transfused neonates had low correlations when fetal hemoglobin concentrations alone were compared with the total volume of red blood cell transfusions (r = 0.35) and with postnatal age (r = 0.18) and the standard errors of prediction were all approximately 17. The correlations found between concentrations of fetal hemoglobin and age in transfused neonates were poorer than those reported in earlier nontransfused infant studies. Previous studies have also shown that neonatal blood containing fetal hemoglobin interferes with the spectrophotometric measurements of carboxyhemoglobin and oxyhemoglobin. Because of the imprecision in the predictions of fetal hemoglobin using age, weight, or the volume of transfusion, we conclude that fetal hemoglobin should be measured if accurate spectrophotometric determinations of carboxyhemoglobin and oxyhemoglobin are desired.

Blood Transfusion↗
PubMed1991

Changes in oxygen measurements when whole blood is stored in iced plastic or glass syringes.

Tonometered whole-blood and plasma specimens were tested in plastic and glass syringes to determine whether clinically significant changes in gas tensions occur during sample storage. When whole blood was tonometered with 60 and 100 mL/L (6% and 10%) oxygen and then stored for 30 min in iced plastic syringes, the pO2 of the samples remained stable (mean change = +0.4 and +0.8 mmHg, respectively). However, for 140 mL/L (14%) oxygen tonometry, the pO2 increased significantly (mean change = +8.4 mmHg; P less than 0.0001). When tonometered plasma was stored in iced plastic syringes, the pO2 increased progressively at all three concentrations, with the smallest change occurring at 140 mL/L (mean change = +12.6 mmHg) and the greatest at 60 mL/L oxygen (mean change = +20.9 mmHg). In contrast, when iced glass syringes were used for storing plasma or whole blood, no clinically significant changes in pO2 were found at any of the tonometered oxygen values for 60 min. When whole blood was stored in plastic syringes at ambient temperature for 30 min, again no clinically significant changes in pO2 were found at these tonometry conditions. Apparently, some blood gas samples stored in iced plastic syringes may yield clinically significant errors in oxygen tension.

Blood Gas Analysis↗
PubMed1990

Abnormal DNA ploidy and proliferative patterns in superficial colonic epithelium adjacent to colorectal cancer.

Superficial colonic cells were taken from normal-appearing mucosa at 2, 5, and 10 cm proximal and distal to colorectal cancer margins in 37 patients. The DNA ploidy and proliferative pattern of each sample were determined using flow cytometry. In 11 patients, histology of mucosal sections from the same sites also was analyzed. We found a higher frequency of aneuploidy than previously reported in mucosa up to 10 cm from a colorectal cancer; 62% (23/37) of the primary cancers were aneuploid, and of these, 48% (11/23) were associated with adjacent aneuploid mucosa. The mucosa adjacent to the 14 diploid cancers had only diploid characteristics. The proliferative activity (as reflected by synthetic (S) phase fraction) of aneuploid cancers (21.1 +/- 2.0% SEM) and aneuploid mucosa as far as 10 cm away (21.2 +/- 2.1% SEM) was higher than in normal controls (10.2 +/- 0.7% SEM) (P less than 0.0005). Parallel cytology excluded shed cancer cells as an explanation for these findings. Histology showed diffuse, generally mild and reactive, mucosal abnormalities in eight of 11 patients. Ploidy did not correlate with histologic abnormalities. The findings of aneuploidy and high S-phase fraction in uninvolved superficial mucosa provide evidence for a field defect in mucosa adjacent to colorectal cancer and support the concept that the large bowel mucosa behaves as a unit in carcinogenesis.

Adult↗
PubMed1990

Cytoreductive surgery.

The results of experimental studies suggest that cytoreduction has important potential benefits. In the laboratory setting, reduction of tumor burden increases the sensitivity of remaining tumor to chemotherapy and radiation therapy by increasing the proportion of proliferating tumor cells, by decreasing the number of necessary chemotherapeutic cycles necessary to eradicate the tumor, by improving cellular distribution of oxygen and nutrient within the tumor and by reducing the likelihood that resistant clones will develop. The evidence for clinical benefit seems much more limited. In general, a benefit of cytoreduction in extending the survival or disease-free interval appears likely only if there is effective chemotherapy or radiation therapy. Hence, benefits of cytoreduction have been acknowledged in pediatric solid tumors, lymphoma and carcinoma of the ovary, for which effective adjuvant treatments exist. Patients with certain tumors that exhibit biologically favorable characteristics may benefit from cytoreduction, even though the usefulness of other treatment modalities may be minimal. (ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Increased lung water and ascites after massive cocaine overdosage in mice and improved survival related to beta-adrenergic blockage.

STUDY OBJECTIVE: To determine the effect of massive cocaine intoxication on lung water and ascites accumulation and the effect of beta- and alpha-adrenergic blockade on survival in massive cocaine intoxication in the mouse. DESIGN: The effect of massive cocaine intoxication on lung water, ascitic fluid accumulation, and survival following LD 100 doses of intravenous cocaine with and without alpha- and beta-adrenergic blockade was determined. INTERVENTIONS: Cocaine hydrochloride (0.15 mg/g body weight) was administered intravenously with no other interventions; with propranolol hydrochloride intravenously (0.5 mg per mouse) before and after cocaine; and with phentolamine intravenously (10.5 micrograms per mouse) before cocaine. MEASUREMENTS AND MAIN RESULTS: Intravenous cocaine hydrochloride resulted in an increase in lung water (saline controls, 4.17 +/- 1.3 [standard deviation] mg water per g mouse; cocaine hydrochloride, 5.94 +/- 0.9 mg water per g mouse; P less than 0.002). Cocaine hydrochloride always resulted in the accumulation of transudative ascitic fluid (saline controls, no measurable ascitic fluid; cocaine administration, 20.2 +/- 12.9 micrograms per mouse; ascitic fluid protein concentration, 23.5 +/- 8.5 g/L). Propranolol hydrochloride administered before or after intravenous cocaine hydrochloride resulted in a striking reduction in mortality (84 of 84 mice without propranolol died [mortality = 100%]; 7 of 39 mice with propranolol died [mortality = 18%]; P less than 0.001). CONCLUSIONS: Massive cocaine intoxication is associated with increased lung water and transudative ascites. Fluid accumulation is not prevented by either alpha- or beta-adrenergic blockers. Propranolol, administered either before or after cocaine, sharply reduces mortality. The results should be extrapolated to treatment in humans with caution.

Animals↗
PubMed1989

Conservative treatment of distal rectal cancer by local excision.

From 1954 through 1982, 57 patients with invasive, distal rectal cancer had a full-thickness local excision with curative intent. Prognostic criteria and need for further treatment were based on the histopathologic results of the operative specimen. The overall 5-year survival rate was 83.4%. The rectal cancer-specific mortality rate was 10.5%. None of the 27 patients without adverse prognostic factors died from rectal cancer, and for this group local excision alone was sufficient treatment. The only single factors associated with an adverse outcome were mucinous characteristics and full-thickness invasion. Ulceration alone and penetration into the muscularis propria alone were not adverse factors. In the presence of multiple adverse prognostic factors, mucinous characteristics or full-thickness penetration, local excision was inadequate treatment and an abdominal perineal resection was necessary.

Adenocarcinoma↗
PubMed1988

Providing clinical pharmacy services in an AIDS--oncology ambulatory-care clinic.

The activities of a pharmacist in an ambulatory-care AIDS-oncology clinic are described. In December 1984, the chief of the AIDS Activities Division of San Francisco General Hospital's Department of Medicine hired a clinical pharmacist to develop the pharmacokinetics sections of investigational drug protocols, provide drug therapy consultations, and supervise the reorganization of the drug storage and inventory system. Since joining the clinic staff, the pharmacist has become active in a variety of clinical, research, and educational activities. The pharmacist conducts weekly medication refill clinics and developed drug information sheets for clinic patients and health-care professionals. The pharmacist also supervises timely collection of blood samples for serum drug concentration determinations and helps to prepare the investigational drugs for dispensing. The pharmacist developed policies and procedures for the safe handling of antineoplastic agents and standardized the accountability procedures for investigational drugs. The pharmacist also serves as a liaison between the clinic and the hospital's department of pharmacy and as a preceptor of pharmacy students and residents. A clinical pharmacist can make an important contribution to the research and patient-care activities in an AIDS-oncology clinic.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Neurogenic hyperacute ascites in mice.

Four groups of mice were subjected to controlled fatal head trauma and then evaluated for the presence of ascites (neurogenic hyperacute ascites, NHA). The animals died virtually instantaneously and without evidence of maintained pain or suffering. The volume of ascites was determined in one group of animals. Two of the traumatized groups were pretreated, one with the beta-blocker propranolol and the other with the alpha-blocker phentolamine. A fifth, non-traumatized, group which was killed with either inhalation served as a control group. Two more groups of non-traumatized mice were administered either the alpha-adrenergic agonist methoxamine hydrochloride or the beta-agonist isoethrane mesylate before killing by ether inhalation, and then evaluated for ascites. Transudative ascitic fluid was found in 87-100% of untreated traumatized mice and in no control animals. Pretreatment with phentolamine had no effect on the prevalence of ascites. Pretreatment with propranolol produced a significant decrease in the prevalence of ascites compared with trauma alone (P less than 0.001). Isoethrane (beta-agonist) administration caused ascites in 100% of the treated animals. Methoxamine (alpha-agonist) administration did not cause ascites. A previously undescribed consequence of acute brain trauma is described (NHA) which appears to be mediated by beta-sympathetic activity of central origin. NHA is inhibited by beta-blockade and can be simulated with beta-agonist administration.

Acute Disease↗