In vitro radiation response of cells from four human tumors propagated in immune-suppressed mice

Two recently developed clonogenic assays for human tumor cells have been used to measure the in vitro radiation cell survival of four human tumors, a pancreatic carcinoma, a colonic carcinoma, an oat cell carcinoma of the lung, and a melanoma, propagated as xenografts in immune-suppressed mice. The slopes and shoulders of the survival curves for the first three tumors were all similar with Do's, respectively, of 94, 100, and 131 rads and with Dq's, respectively, of 8, 44, and 41 rads, However, melanoma cells from the fourth tumor had a survival curve that differed from those of the other three, both in having a wider shoulder with a Dq of 216 rads and in having a shallower slope with a Do value of 183 rads. It is suggested that the wide shoulder to the melanoma cell survival curve may in part explain the poor response to small fractionated doses of radiotherapy usually observed clinically for this tumor type. However, the data from the other three tumors suggest that differences in radiotherapeutic response seen in the clinic for these tumors cannot be attributed to differences in intrinsic radiosensitivity of the tumor cells.

An in vitro colony assay for human tumours grown in immune-suppressed mice and treated in vivo with cytotoxic agents

An in vitro agar colony technique has been developed for the growth of tumour cells taken directly from human tumours grown in immune-suppressed mice. The novel feature of the technique is the addition of a replenishable liquid phase which permits the maintenance of relatively slowly growing cells. A number of different xenografted tumours have been cultured successfully in this system, with red blood cells added to the agar and using 5% O2 in the gas phase. The technique has been used to assay cell survival in tumours treated in vivo with cytotoxic agents, and examples are given of survival curves obtained from a pancreatic tumours irradiated with gamma-rays and a colonic tumour from mice treated with cyclophosphamide. The results obtained by this in vitro method are in agreement with those from the agar diffusion chamber technique. This culture method has also been successfully used for the growth of cells taken directly from human tumour biopsy samples obtained in the clinic.

Role of cardiac catheterization in infective endocarditis

The benefits and hazards of catheterization and angiography were evaluated in 19 patients with acute aortic and/or mitral endocarditis and heart failure. In 14 patients (74%), the bedside diagnosis of valvular insufficiency and heart failure was proved correct. In three patients with both aortic and mitral valve disease, angiography (without hemodynamic measurements) was necessary to clarify the diagnosis. Angiography detected four aortic aneurysmal erosions that were unsuspected clinically, but missed three others. After angiography, heart failure worsened in two patients with severe progressive aortic insufficiency and one died. Thus, catheterization-angiography was of greatest value if more than one left-sided valve lesion was present, if extravalvular diseases mimicked heart failure, or if extravalvular infection was present. Patients with isolated, clear-cut mitral insufficiency usually do not need these diagnostic procedures, and they are probably contraindicated in patients with severe aortic regurgitation with rapidly progressing heart failure.

Effectiveness of nurse triage in the emergency department of an urban county hospital

The effectiveness of patient triage by a specially trained registered nurse in the emergency department of an urban county hospital, San Francisco General Hospital, was evaluated over a three-month period. Ambulatory patients thought to have nonemergent illnesses were directed to the Walk-In Service for physician evaluation and treatment; the remainder were seen in the Emergency Service. In three months, 11,329 patients registered for care, and 4,150 (37%) were referred to the Walk-In Service. Of the 77 admitted patients, six were thought to require treatment within a few hours, 67 within hours to days, and four were considered elective admissions. There were no deaths. Error in triage was about equally divided between mistaken diagnosis and underestimated severity of illnes. The overall accuracy of triage was 98%.

Enhancement studies on algae and isolated chloroplasts. Part II. Enhancement of oxygen evolution in intact chloroplasts

Intact isolated chloroplasts were shown to exhibit a characteristic three-phase pattern of development of oxygen evolution activity. The first phase, Phase I, appeared to be an equilibration phase in which the isolated chloroplasts adapted to the conditions on the electrode surface. It was characterised by a rapidly increasing rate of oxygen evolution accompanied by decreasing enhancement signals. The second phase, Phase II, was an intermediate phase in which the rate of oxygen evolution was maximal and no enhancement was observed. In the last phase, Phase III, the rate of oxygen fell again, normal enhancement was still missing, but the samples appeared to undergo slow adaptive changes closely related to the State I-State II changes previously reported for whole cell systems. The concentrations of Mg2+ within the chloroplast were shown to play an important role in the control of the development of both the oxygen evolution and enhancement signals. It was shown how these signals could be explained in terms of a model that was consistent with that developed in Part I of this investigation to account for the variability of enhancement of the alga Chlorella pyrenoidosa.

Serratia marcescens endocarditis: a regional illness associated with intravenous drug abuse

From 1969 to 1974, 19 cases of Serratia marcescens endocarditis were observed in the San Francisco Bay Area. Seventeen patients were intravenous drug users, and Serratia caused 14% of all addict-associated endocarditis in San Francisco. Serratia strains were nonpigmented and had typical antibiotic sensitivities, except that 9 of the isolates exhibited colonial variation, with each variant having different antibiotic sensitivities. Aortic or mitral valves were involved in 13 patients, and heart failure developed in 9 of these. Twelve patients had embolic episodes to brain, iliofemoral arteries, or lung. Five of 6 patients with tricuspid valvulitis were cured by antibiotics either with (1) or without excision of the valve. All 12 patients with aortic or mitral valvulitis treated medically died; 11 had unremitting sepsis. Aortic valve replacement and antibiotics were effective in 1. Gentamicin combined with either carbenicillin or chloramphenicol was the most effective treatment regimen.

Humoral immunity to a metabolite of halothane, fluroxene, and enflurane

Trifluoroacetate, a common metabolite of halothane, fluroxene, and enflurane, conjugated to guinea-pig albumin elicits specific serum antibody in guinea pigs. Two classes of antibodies were found: hemolytic, gamma-2, and anaphylactic, gamma-1. Repeated injections of the antigen, trifluoroacetyl-guinea pig albumin, often led to disappearance of circulating antibodies.

Correlation between specific immunity to a metabolite of halothane and hepatic lesions after multiple exposures

A correlation between the use of halogenated anesthetic agents and liver necrosis is not yet established in man. In an attempt to resolve this dilemma, guinea pigs were immunized with a complex of guinea-pig albumin and trifluoroacetate (TFA), a common metabolite of halothane and fluorexene, and then exposed to halothane on multiple occasions. Histology and liver-function tests showed no difference in the incidence of liver damage between groups of animals immune to TFA with cellular immunity and untreated control animals. However, a difference in the liver enzyme levels was seen between controls and animals showing humoral immunity.

The role of valve replacement in the treatment of fungal endocarditis

The role of valve replacement in the treatment of fungal endocarditis has not been defined. The diagnosis of fungal endocarditis was made in 11 patients, 8 before death and 3 at autopsy. Nine patients were infected with Candida species, one with Torulopsis glabrada and one with Aspergillus. None of the 8 patients whose disease was diagnosed during life was cured despite up to 160 days of amphotericin B therapy. All required valve replacement for heart failure (1 patient), emboli (1 patient, or both (6 patients). We recommend early valve replacement for fungal endocarditis before the onset of heart failure and emboli.

Dobutamine: development of a new catecholamine to selectively increase cardiac contractility

We systematically modified isoproterenol's chemical structure to reduce chronotropic, arrhythmogenic, and vascular side effects. Experiments on dogs showed that the resulting drug, dobutamine, had an inotropic efficacy as great as that of epinephrine due to a direct action on beta1 cardiac receptors. However, unlike epinephrine, dobutamine's effect on alpha and beta2 vascular receptors was slight. At equivalent inotropic doses, dobutamine had less than a fourth of the chronotropic effect of isoproterenol. Desmethylimipramine (DMI), which blocks the sympathetic nerve fiber uptake mechanism, had no effect on dobutamine's actions. In contrast, DMI antagonized dopamine's inotropic effect, and marked chronotropic and pressor responses occurred when we used doses of dopamine large enough to elicit a direct inotropic effect. Dobutamine increased the contractility of isolated cat papillary muscles more but the automaticity less than did isoproterenol. In ischemic dog hearts, dobutamine lacked significant arrhythmic activity, whereas dopamine, norepinephrine, and isoproterenol caused severe ectopic activity. In dogs with experimentally induced low cardiac contractility, low cardiac output, and hypotension, dobutamine produced dose-related increases in cardiac contractility and output, restored arterial blood pressure, and reduced total peripheral resistance slightly. In contrast, isoproterenol failed to restore blood pressure, had only a meager effect on cardiac contractility and output, cuased extreme tachycardia, and lowered peripheral resistance more than did dobutamine. Norepinephrine, which did not increase cardiac contractility or output as much as dobutamine, excessively elevated peripheral resistance and arterial blood pressure.