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Biomedical subjects

J E Howard

Publications and source records attributed to J E Howard.

At least 37 records · Page 2Linked to original sources
PubMed1986

Evoked potentials in hysteria and malingering.

Evoked potentials are often helpful in confirming the nonorganic nature of sensory symptoms in hysteria and malingering. In a retrospective analysis, such cases were found to comprise approximately 1% of referrals to a university hospital laboratory. However, the diagnostic usefulness of electrophysiologic tests is limited in some clinical settings: normal responses may be encountered in subjects with certain organic deficits, and "abnormal" responses can sometimes be produced voluntarily by normal subjects. In malingering--as opposed to hysteria--the role of the technologist in monitoring patient compliance with the test procedure is particularly important. Like other laboratory investigations, evoked potential findings must be interpreted within the context of each clinical situation, and with full appreciation of the sensitivities and specificities of the tests.

Adult↗
PubMed1983

Cisplatin, vindesine and bleomycin (CVB) combination chemotherapy of advanced non-small cell lung cancer.

Fifty-four patients with advanced squamous, large-cell or adeno-carcinoma of the lung were treated with a three drug regimen of high-dose cisplatin, vindesine and a four-day bleomycin infusion (CVB). All patients had measurable disease; none had previously received chemotherapy. Of 52 patients evaluable for response, 20 (38%) had complete or partial remissions. The median duration of remission was 8 months (range, 6 1/2-19+ months), with eight patients continuing in remission. The median duration of survival for responding patients was 16 months versus five months for nonresponding patients (P greater than 0.001). Toxicity included mild to moderate myelosuppression, peripheral neuropathy, and nephrotoxicity, and was generally manageable. The addition of a four-day bleomycin infusion did not appear to offer a significant advantage over the combination of high-dose cisplatin and vindesine in the treatment of NSCLC. The response rate and survival duration produced by the CVB protocol were similar to those reported for the two-drug combination of vindesine and high-dose cisplatin.

Adenocarcinoma↗
PubMed1982

Chemical hyperthyroidism: serum triiodothyronine levels in clinically euthyroid individuals treated with levothyroxine.

We have observed many patients treated with levothyroxine sodium who have elevated serum thyroxine (T4) levels but appear clinically euthyroid. Such patients generally have normal serum triiodothyronine (T3) values. A retrospective review at The Johns Hopkins Hospital, Baltimore, comparing the correlation of T3 and T4 values in levothyroxine-treated patients with that in patients not so treated was carried out from 1977 to 1979. Mean free thyroxine index (FTI) value in 104 levothyroxine-treated patients was 4.70 +/- 0.2 and mean T3 value was 177 +/- 9 ng/dL. In a group of 50 hyperthyroid patients, mean FTI value was 7.26. +/- 0.5, with a mean T3 value of 389 +/- 26 ng/dL. In 71 euthyroid patients, mean FTI value was 2.36 +/- 0.1, with a T3 value of 137 +/- 3 ng/dL. Computed ratios of T3 to FTI and T3 to T4 were significantly lower in the group treated with levothyroxine than in either the hyperthyroid or euthyroid nontreated groups. Levothyroxine-treated patients with high T4 levels but normal T3 levels were clinically euthyroid. Patients not treated with levothyroxine with similarly elevated T4 levels had elevated T3 levels and were clinically hyperthyroid. It is concluded that lower relative T3 levels in levothyroxine-treated patients may explain why these patients appear clinically euthyroid despite elevated T4 values. Serum T3 determination is the procedure of choice for evaluation of levothyroxine-treated individuals. Furthermore, an elevated FTI value in such an individual does not, in itself, dictate need to reduce dosage.

Drug Administration Schedule↗
PubMed1981

Phosphocitrate inhibits mitochondrial and cytosolic accumulation of calcium in kidney cells in vivo.

Synthetic 3-phosphocitrate, an extremely potent inhibitor of calcium phosphate crystallization as determined in a nonbiological physical-chemical assay, has many similarities to a mitochondrial factor that inhibits crystallization of nondiffracting amorphous calcium phosphate. In order to determine whether phosphocitrate can prevent uptake and crystallization of calcium phosphate in mitochondria in vivo, it was administered intraperitoneally to animals given large daily doses of calcium gluconate or parathyroid hormone, a regimen that causes massive accumulation and crystallization of calcium phosphate in the mitochondria and cytosol of renal tubule cells in vivo. Administration of phosphocitrate greatly reduced the net uptake of Ca2+ by the kidneys and prevented the appearance of apatite-like crystalline structures within the mitochondrial matrix and cytosol of renal tubule cells. Phosphocitrate, which is a poor chelator of Ca2+, did not reduce the hypercalcemia induced by either agent. These in vivo observations therefore indicate that phosphocitrate acts primarily at the cellular level to prevent the extensive accumulation of calcium phosphate in kidney cells by inhibiting the mitochondrial accumulation or crystallization of calcium phosphate.

Animals↗
PubMed1980

Synthesis and characterization of phosphocitric acid, a potent inhibitor of hydroxylapatite crystal growth.

Human urine and extracts of rat liver mitochondria contain apparently identical agents capable of inhibiting the precipitation or crystallization of calcium phosphate. Its general properties, as well as 1H NMR and mass spectra, have suggested that the agent is phosphocitric acid. This paper reports the synthesis of phosphocitric acid via the phosphorylation of triethyl citrate with o-phenylene phosphochloridate, hydrogenolysis of the product to yield triethyl phosphocitrate, hydrolytic removal of the blocking ethyl groups and also chromatographic purification. An enzymatic assay of phosphocitrate is described. Synthetic phosphocitrate was found to be an exceedingly potent inhibitor of the growth of hydroxylapatite seed crystals in a medium supersaturated with respect to Ca2+ and phosphate. Comparative assays showed phosphocitrate to be much more potent than the most active precipitation-crystallization inhibitors previously reported, which include pyrophosphate and ATP. 14C-Labeled phosphocitrate was bound very tightly to hydroxylapatite crystals. Such binding appeared to be essential for its inhibitory activity on crystal growth. Citrate added before but not after, phosphocitrate greatly enhanced the inhibitory potency of the latter. This enhancement effect was not given by other tricarboxylic acids. The monoethyl ester of phosphocitrate had no inhibitory effect on hydroxylapatite crystal growth.

Calcium Phosphates↗
PubMed1980

Effect of positive end-expiratory pressure on dynamic respiratory compliance in neonates.

A simplified method of determining dynamic respiratory compliance (C dyn) in the newborn is described. Studies were performed during mechanical ventilation on 24 infants with respiratory distress syndrome (RDS) and 6 infants without RDS. Cdyn was evaluated at pressure settinghs of 20/0, 25/5 and 30/10 cm H2O. Significant decreases (p < 0.05) in Cdyn were noted with each increase in end-expiratory pressure setting. The values for Cdyn in RDS patients obtained by this method closely approximated previously published data for lung compliance in babies with RDS. This simple and reproducible method may be useful in following the course of illness in infants with RDS.

Forced Expiratory Flow Rates↗
PubMed1978

Trimethoprim-sulfamethoxazole vs sulfamethoxazole for acute urinary tract infections in children.

A total of 118 children between 6 months and 10 years of age with acute urinary tract infection were treated in a random; double-blind manner with 12 mg/kg/day of trimethoprim-sulfamethoxazole (61 patients) or 50 mg/kg/day of sulfamethoxazole (57 patients) for ten days. Mean trimethoprim and sulfamethoxazole susceptibilities of Escherichia coli isolated from these patients were 1.2 and 0.6 microgram/ml, respectively. Mean serum concentrations of trimethoprim and sulfamethoxazole were 1.8 and 62 microgram/ml, respectively, one hour after the dose. Of the children who completed the ten days of prescribed medication, clinical and bacteriological cure was confirmed immediately after treatment for all but one patient in each group. Most patients in each treatment group with recurrent infections had underlying urological abnormalities. Severe hematological, renal, or hepatic toxicity requiring interruption of treatment was not encountered. No advantage of trimethoprim-sulfamethoxazole over sulfamethoxazole alone for acute urinary tract infection was demonstrated.

Acute Disease↗
PubMed1976

Lysis of donor RBC during plateletpheresis with a blood processor.

Erythrocytes of a normal volunteer blood donor were grossly hemolyzed during plateletpheresis with the use of a continuous-flow centrifuge. Extensive studies of the donor's red blood cells (RBC) showed no abnormalities. Bank blood was then processed in the centrifuge in a manner identical to the prescribed in vivo plateletpheresis. Gross hemolysis consistently resulted when the tubing on the downstream side of the blood pump was partially obstructed by a twist. This experience calls for caution when assembling the harness of an extracorporeal circuit employing a pump. The tubing should be inspected to ensure the absence of obstructions.

Adult↗
PubMed1976

Otitis media of infancy and early childhood. A double-blind study of four treatment regimens.

A double-blind, randomized trial of four antimicrobial regimens was conducted in 383 infants and children with acute otitis media. The drugs used were penicillin V, amoxicillin trihydrate, erythromycin estolate, and erythromycin estolate with trisulfapyrimidines. Aspiration of middle ear fluid for culture was done before treatment and repeated during treatment if fluid persisted. Etiologic bacteria were most commonly pneumococci (31%) or Haemophilus sp (22%), and an additional 5% of patients had both organisms. Amoxicillin was the most effective in promoting initial response in pneumococcal infection. For Haemophilus infections, the cure rates with amoxicillin and the erythromycin-trisulfapyrimidines mixture were significantly better than with the other two regimens, and serous otitis did not occur during the follow-up period; however, new episodes of otitis were comparable in the four groups. Amoxicillin and the erythromycin estolate-trisulfapyrimidines combination appear to be somewhat more effective than penicillin V or erythromycin estolate.

Acute Disease↗
PubMed1976

Post-transfusion thrombocytopenic purpura: a case report.

Post-transfusion thrombocytopenic purpura (PTTP) is a rare syndrome which was first brought to widespread attention by Shulman et al. Eighteen cases have been reported. The present report describes an additional patient, a multiparous female who developed petechia 7 days after blood transfusion. The patient's serum contained anti-P1A1 antibodies and her own platelets were P1A1-negative. She was treated with prednisone and recovered spontaneously without exchange transfusion of whole blood or plasma.

Aged↗