A computerized hospital maintenance system

The Biomedical Instrumentation Department at Thomas Jefferson University Hospital maintains most of the clinical equipment owned by the hospital and provides support to six other hospitals, as well. In order to document these services, a computerized support system has been developed. This system maintains the inventory of equipment, documents the occurrence of repair and preventive maintenance procedures, generates lists of items due for maintenance and inspection, and prints reports and summaries of all activities performed by department staff. The system was designed for ease of use and requires a minimum of training for personnel who use it.

Metabolites of 1,2,3,4-tetrachlorobenzene in monkey urine

[14C(U)]-Labeled 1,2,3,4-tetrachlorobenzene was administered orally to squirrel monkeys. Urine was collected from these animals, pooled and analyzed for metabolites by thin-layer chromatography, high-performance liquid chromatography, and gas chromatography-mass spectroscopy. N-Acetyl-s-(2,3,4,5-tetrachlorophenyl) cysteine was shown to be the major metabolite and accounted for 85% of the radioactivity found in urine. A minor metabolite was identified as 2,3,4,5-tetrachlorophenol. This study demonstrates for the first time that an N-acetyl cysteine conjugate has been isolated and identified as metabolite of a chlorinated benzene. This pattern of chlorobenzene metabolism is significantly different from the one obtained with the rat and rabbit, where tetrachlorophenols constitute the major metabolites.

Temporal evolution of the human coronary collateral circulation after myocardial infarction

An analysis of the coronary collateral circulation in a consecutive series of 116 postinfarction angiograms from patients with persistent 100% occlusion of their infarct artery is reported. Patients were classified into four groups according to the interval between acute infarction and angiography. Of 42 patients studied within 6 hours of infarction (Group I), 52% had no evidence of any coronary collateral development as compared with only 8% (1 of 16 patients) studied 1 day to 2 weeks after infarction (Group II). Virtually all patients studied beyond 2 weeks after myocardial infarction (14 to 45 days, Group III) and later than 45 days (Group IV) had visible collateral flow. Angiographically "well developed" collateral channels were seen in only 16% of Group I patients compared with 62, 75 and 84% of patients in Groups II to IV, respectively. Of six patients studied twice, on the day of the infarction and 2 weeks later, only one patient had collateral vessels on the day of infarction, whereas all six patients did at follow-up study. Group I patients were studied as part of a randomized acute myocardial infarction reperfusion trial, whereas the other patients were referred for angiography primarily because of post-infarction ischemia. Within the limitations imposed by the patient selection process, it is concluded that well developed coronary collateral vessels are rarely present at the time of infarction. After infarction, they develop rapidly and are generally demonstrable within 2 weeks. It may also be inferred that the preservation of ischemic myocardium by well developed coronary collateral vessels at the time of myocardial infarction may be an uncommon occurrence.

The interactions between nucleic acids and polyamines

Changes in the NMR chemical shifts of protons adjacent to the nitrogen atoms of Spermidine which are undergoing protonation have been measured by two-dimensional heteronuclear coupled NMR. Data thus obtained measure the dependence of the state of protonation of individual nitrogens on the pH, and permit calculation of the microprotonation constants of Spermidine and the concentrations of all of the variously protonated Spermidine species present at any pH.

A randomized, angiographically controlled trial of intracoronary streptokinase in acute myocardial infarction

Fifty-five patients with acute myocardial infarction evaluated within 4 hours of the onset of symptoms were entered into an angiographically controlled trial of intracoronary streptokinase (IC STK). Forty-three patients with total occlusion of their infarct artery were randomized to either IC STK or intracoronary nitroglycerin (IC NTG), and 12 patients with less-than-complete occlusion received only IC NTG. Reperfusion of a totally occluded vessel was achieved in 69% of STK patients and 17% of IC NTG patients. Time from onset of symptoms to peak CK activity was significantly shorter in reperfused patients and patients with subtotal occlusion on initial angiography than in patients with total occlusion who were not reperfused (p less than 0.0001). Comparison of radionuclide ejection fractions (EF) determined acutely and 10 to 14 days after infarction failed to show improvement in either the STK or IC NTG group (mean decrease of 2.8% and 0.4%, respectively). In contrast, patients with subtotal occlusion on baseline angiography demonstrated a significant (p = 0.05) spontaneous improvement in EF over 2 weeks (7.3% increase).

Insulin secretion and action in noninsulin-dependent diabetes mellitus. Is insulin resistance secondary to hypoinsulinemia?

The insulin-stimulated glucose metabolic clearance rate, assessed by the insulin clamp technique, was compared in 40 normal subjects and 40 age- and weight-matched patients with noninsulin-dependent diabetes mellitus. These studies were conducted at steady-state plasma insulin levels of approximately 100 microU/ml, and the mean (+/- standard error of the mean) glucose metabolic clearance rate of patients with noninsulin-dependent diabetes mellitus was 81 +/- 9 ml/m2 per minute, as compared with a value of 235 +/- 14 ml/m2 per minute for normal subjects. This difference was highly statistically significant (p less than 0.001) and documents the extreme resistance to insulin-stimulated glucose utilization seen in noninsulin-dependent diabetes mellitus. Patients with noninsulin-dependent diabetes mellitus were also shown to have a lower than normal plasma insulin response to an oral glucose challenge. In contrast, ambient plasma insulin concentrations of normal subjects and patients with noninsulin-dependent diabetes mellitus were found to be quite comparable when measured throughout the day in response to the ingestion of conventional mixed meals. Consequently, absolute hypoinsulinemia is not characteristic of patients with noninsulin-dependent diabetes mellitus under conditions of daily living. Finally, the ability of intensive insulin treatment to improve insulin resistance was studied after one and six weeks of therapy. These results indicated that successful control of hyperglycemia led to a significant improvement in insulin action as early as one week after the initiation of insulin therapy, with no further changes noted after prolonged insulin administration. The degree to which insulin action approached normal values was greater when studies were carried out at circulating insulin levels of approximately 2,000 microU/ml as compared with insulin levels of approximately 100 microU/ml, but in both instances insulin-treated diabetic patients remained insulin-resistant as compared with normal subjects. These results have corroborated the fact that abnormalities of both insulin action and secretion can be documented in patients with noninsulin-dependent diabetes mellitus. However, patients with noninsulin-dependent diabetes mellitus were not found to be absolutely hypoinsulinemic in their daily existence, and control of their hyperglycemia with exogenous insulin did not restore insulin-stimulated glucose utilization to normal. Consequently, these data are not consistent with the view that the insulin resistance in noninsulin-dependent diabetes mellitus is entirely a secondary consequence of the hypoinsulinemia presumed to be present in these patients.

Stimulation of sugar transport in cultured heart cells by triiodothyronine (T3) covalently bound to red blood cells and by T3 in the presence of serum

T3, covalently bound to red blood cells (RBCs), stimulated the uptake rate of 2-deoxy-D-glucose (2-DOG) in cultured chick embryo heart cells. The response, measured 6 h after exposure, was at least the same than that to free T3. An inhibitor of rhodamine-T3 internalization, bacitracin, did not affect the stimulation of sugar uptake by T3 regardless of whether T3 was covalently bound or free. Pretreatment of RBC-T3 with anti-T3 immunoglobulin G completely blocked the effect of T3, whereas normal rabbit immunoglobulin G failed to do so. Addition of 5% chick serum to the medium stimulated 2-DOG uptake to 144% of the control at 6 h. Adding T3 (10 nM) to the serum-containing medium increased 2-DOG uptake to 171% of the control. The effect of T3 alone or in the presence of serum was not inhibited by cycloheximide, puromycin, or actinomycin D. A T3 dose response curve, in medium containing 10% dehormonized serum, showed enhancement of the T3 effect when compared with the curve obtained in the serum-free medium. The minimal effective concentration of T3 was 10 pM in the presence of serum and 100 pM in its absence. The slope of the linear portion of the dose response curve was greatly increased and the maximal response markedly enhanced by serum. The ED50 was 0.33 nM vs. 0.43 nM in terms of total T3 concentration and 0.16 nM vs. 0.43 nM in terms of free T3 in the presence or absence of serum, respectively. These data suggest that T3, in physiological concentrations, activates sugar transport through an external contact with the cell surface.

Partial purification and characterization of succinyl-CoA synthetase from Saccharomyces cerevisiae

Succinyl-CoA synthetase from Saccharomyces cerevisiae was partially purified (20-fold) with a yield of 44%. The Michaelis-Menten constants were determined: Km (succinate) = 17 mM; Km (ATP) = 0.13 mM; Km (CoA) = 0.03 mM. The succinyl-CoA synthetase has a molecular weight of about 80000 dalton (as determined by polyacrylamide gradient gel electrophoresis). The pH optimum is at 6.0. During fermentation the activity of succinyl-CoA synthetase is lower than in aerobically grown yeast cells. The presence of succinyl-CoA synthetase in fermenting yeasts may be regarded as an indication for the oxidative formation of succinate. In fermenting yeast cells succinyl-CoA synthetase is repressed by glucose if ammonium sulphate serves as nitrogen source. This catabolite repression is not observed with disaccharides or when amino acids are used as nitrogen source.

Unusual echocardiographic findings in primary pulmonary hypertension

A patient with primary pulmonary hypertension showed unusual echocardiographic findings. These included echoes arising from an intracavitary right ventricular muscle band mimicking a divided interventricular septum. The hemodynamic study excluded subvalvular right ventricular obstruction. Severe right ventricular hypertrophy was also present. Both findings were probably related and may possibly be found in similar cases with severe right ventricular hypertrophy, especially due to primary pulmonary hypertension. The right ventricular muscle band possibly represented hypertrophied moderator band.

Anti-inflammatory action of dexamethasone in vitrectomy infusion fluid

Vitrectomy and lensectomy were performed in rabbits with infusion fluid containing dexamethasone. No ocular toxicity was observed in eyes that received dexamethasone up to a concentration of 400 micrograms/ml. Utilizing sensitive radioimmunoassay techniques after surgery, we observed significant reduction in ocular albumin levels in eyes treated with dexamethasone when compared with control eyes in which dexamethasone was not used. However, there was no significant difference in immunoglobulin levels between eyes from both groups.

Lacrimal gland adenoid cystic carcinoma: intracranial and extracranial en bloc resection

Adenoid cystic carcinoma of the lacrimal gland is a rare tumor, although it is the malignancy most frequently arising in the gland. Treatment has been unsuccessful generally, with a 15-year survival of less than 20 percent. Our experience with this tumor in a 61-year-old woman has led to a proposal for therapeutic management based on awareness of the lesion's natural history, an understanding of regional anatomy, and familiarity with therapies reported in the literature. The feasibility of adequate tumor ablation is determined from preoperative evaluation, including CT scan, initial exploratory craniotomy, and frozen-section examination of the cranial nerves transversing the orbit. Once resectability is confirmed, "curative" intracranial and extracranial en bloc resection is performed, including the tumor, the lacrimal gland, and all contiguous structures. The defect is immediately resurfaced with and "ice cream cone" forehead flap in anticipation of adjuvant radiotherapy. An orbital prosthesis is fitted as soon as the radiation reaction subsides, and a postablative CT scan is obtained as the baseline for follow-up. It remains to be seen whether this application of the technology of CT scanning and the techniques of craniofacial surgery will improve the prognosis for adenoid cystic carcinoma arising in the lacrimal gland.