Ascorbic acid potentiates the inhibitory effect of dopamine on prolactin release: a putative supplementary agent for PIF

Dopamine has a catechol group which can be easily oxidized by mild oxidizing agents. Ascorbic acid has been routinely added to a dopamine solution in order to protect it from oxidation. We have examined the effect of ascorbic acid on dopaminergic inhibition of prolactin release. Male rat pituitary cells were dispersed using trypsin and cultured for 5-7 days before experiments. Ascorbic acid did not stimulate nor inhibit prolactin release in both static monolayer culture and dynamic perifusion systems, but potentiated by approximately 100 times the inhibitory effect of dopamine on prolactin release. In order to differentiate chemical protection from potentiation, we tested the potentiation effect of isoascorbic acid which is an epimer of biologically active L-ascorbic acid but is biologically less active. Our results indicated that isoascorbic acid caused less potentiation of the dopaminergic effect on prolactin release than did ascorbic acid. In a perifusion system, a high concentration of dopamine (100 nmol/l) was unable to inhibit prolactin release for a 1 h experimental period, but a low concentration of dopamine (10 nmol/l) plus ascorbic acid (10 mumol/l) inhibited prolactin release for the entire 1 h perifusion period. There is a strong possibility that ascorbic acid may be a physiological supplementary agent for the prolactin-release inhibiting factor (PIF) since the blood concentration of ascorbic acid is rather high (23-85 mumol/l).

Phase I and pharmacokinetic study of high volume intraperitoneal aclacinomycin-A (Aclarubicin)

Aclacinomycin-A (Aclarubicin) is a relatively new anthracycline antibiotic with potential activity against ovarian cancer. Eight patients with various malignancies (4 ovary, 1 breast and ovary, 1 breast, 1 colon, 1 leiomyosarcoma) and intraperitoneal disease were treated in a Phase I trial with escalating doses of intraperitoneal Aclacinomycin. Drug treatments were administered through a peritoneal catheter in a 2 liter fluid volume (1.5% Dianeal). Seventeen cycles were administered with doses ranging from 25 to 75 mg of Aclacinomycin. Pharmacokinetic studies were carried out in 7 patients. Although high concentrations of Aclacinomycin could be obtained in the peritoneal cavity no drug was detected in the plasma. The major dose-limiting toxicity was chemical peritonitis. Two patients had reduction in the amount of ascites. The recommended dose for Phase II trials is Aclacinomycin 50 mg in 2 liters given every 2 weeks.

Management of flail chest

This paper compares the management of two groups of patients with flail chest. The 25 patients in group 1 had a flail chest without other significant injuries or shock, whereas the 57 in group 2 had a flail chest with multiple injuries, shock or both. The group 1 patients were treated with repeated multiple intercostal nerve blocks or high segmental epidural analgesia, oxygen, intensive chest physiotherapy, fluid restriction, furosemide diuretics, methylprednisolone sodium succinate and colloid infusion in an intensive care unit. In addition to these measures, the group 2 patients underwent endotracheal intubation and assisted mechanical ventilation with a volume respirator that provided continuous positive airway pressure and positive end-expiratory pressure. Of the 57 group 2 patients 36 required prolonged ventilation, eventually through a tracheostomy, because of severe head injury, pneumonia, severe facial injury, quadriplegia, pre-existing lung disease or severe sepsis. However, tracheostomy was avoided in the other 21 patients in group 2. There were no deaths in group 1, but 8 (14%) of the patients in group 2 died. These results show that avoidance of tracheostomy and ventilation in selected patients with flail chest is consistent with a low morbidity and mortality.

Decreased antithrombin III level associated with failure of anticoagulation

A 67-year-old man with adenocarcinoma of the colon had recurrent pulmonary emboli. The patient's level of serum antithrombin III was found to be below normal. Heparin therapy led to further reduction, resulting in failure of adequate anticoagulation. The patient subsequently died of massive pulmonary emboli despite heparin therapy. We believe the antithrombin III level should be routinely determined for patients receiving heparin therapy.

Enzymatic activity of dystrophic chicken sarcoplasmic reticulum

We have isolated sarcoplasmic reticulum from normal and dystrophic chicken muscle, using an improved isolation procedure. Dystrophic sarcoplasmic reticulum has a reduced level of calcium-sensitive ATPase activity, phosphoenzyme formation, and steady-state calcium transport. Anion-stimulated calcium transport by dystrophic sarcoplasmic reticulum is also reduced when measured under the proper conditions, and dystrophic sarcoplasmic reticulum shows no alteration in calcium efflux rate. Active calcium phosphate loading of the normal and dystrophic sarcoplasmic reticulum preparations indicates that a reduced percentage jof the dystrophic vesicles are capable of active calcium transport. The loaded dystrophic sarcoplasmic reticulum vesicles exhibit the same relative reductions in enzymatic activity as the starting sarcoplasmic reticulum preparations. However, the enzyme activities of normal and dystrophic sarcoplasmic reticulum are similar in the presence of detergent and exogenous phospholipid. On the basis of these results, we suggest that the lipid microenvironment of the dystrophic enzyme is altered.

Cross-linking of the (Ca2+ + Mg2+)-ATPase protein

The addition of cupric-1,10,-phenanthroline, a cross-linking catalyst, to sarcoplasmic reticulum membranes caused protein sulfhydryl groups to form disulfide bridges. Following a short exposure to the catalyst (15 s, 22 degrees C) most of the protein was in a dimeric form (Mr = 248 000). Longer exposure times resulted in the formation of trimers, tetramers and other oligomers too large to enter the gel. At low temperatures (4 degrees C) dimer formation predominates even for exposure times as long as 5 min. Cross-linking in the presence of 7.5 mM Triton X-100 (a concentration that resulted in clearing of the membrane suspension and thus solubilization of the membrane components) showed the appearance of a considerable dimer fraction, however, most of the (Ca2+ + Mg2+)-ATPase protein appeared as a monomer. Following 1 min of cross-linking at 22 degrees C, freeze-etched membranes showed no alteration in the number or appearance of 80 A intramembranous particles. Thus extensive cross-linking of the (Ca2+ + Mg2+)-ATPase protein can occur without disruption of the normal position of the intramembrane portion of the molecule.

Cross-linking of the (Ca2+ + Mg2+)-ATPase protein

The addition of cupric-1,10,-phenanthroline, a cross-linking catalyst, to sarcoplasmic reticulum membranes caused protein sulfhydryl groups to form disulfide bridges. Following a short exposure to the catalyst (15 s, 22 degrees C) most of the protein was in a dimeric form (Mr = 248,000). Longer exposure times resulted in the formation of trimers, tetramers and other oligomers too large to enter the gel. At low temperatures (4 degrees C) dimer formation predominates, even for exposure times as long as 5 min. Cross-linking in the presence of 7.5 mM Triton X-100 (a concentration that resulted in clearing of the membrane suspension and thus solubilization of the membrane components) showed the appearance of a considerable dimer fraction, however, most of the (Ca2+ + Mg2+)-ATPase protein appeared as a monomer. Following 1 min of cross-linking at 22 degrees C, freeze-etched membranes showed no alteration in the number or appearance of 80 A intramembranous particles. Thus extensive cross-linking of the (Ca2+ + Mg2+)-ATPase protein can occur without disruption of the normal position of the intramembrane portion of the molecule.

Differential pulse polarographic determination of clorazepate monopotassium and dipotassium

Polarographic investigation of clorazepate monopotassium and dipotassium showed two cathodic waves at about -1.28 and -1.66 v. The cathodic wave associated with clorazepate monopotassium or dipotassium at about -1.66 v was a pH-independent, diffusion-controlled wave. This wave was used to develop a specific stability-indicating procedure for clorazepate monopotassium and dipotassium in the presence of their degradation products, namely, nordiazepam, 2-amino-5-chlorobenzophenone, and glycine. The method involves a 10(-2) M LiOH-10(-1) M LiCl extraction of the active ingredient from the formulation, filtration, dilution with the same supporting electrolyte, and then use of the standard addition technique for drug quantitation in capsules. Typical fomulation excipients did not interfere with the analysis. Accuracy and precision of the procedure were 99.55 +/- 0.68%.

GLC determination of warfarin in human plasma

A specific and quantitative GLC method for warfarin in human plasma is described. The procedure uses papaverine as the internal standard and involves a dichloroethane extraction of the acidified specimen. The organic extract is evaporated, and the evaporated extract is dissolved in 50 microliter of chloroform. Aliquots of 2-3 microliter are injected into a gas chromatograph equipped with a flame-ionization detector. The sensitivity of the method is such that 0.3 microgram of intact warfarin can be detected in 1 ml of plasma. Statistical analyses indicate a recovery of 97.26 +/- 1.89% SD. The procedure was successfully applied to plasma drug level studies in humans.

Analysis of homatropine methylbromide dosage forms

A stability-indicating method of analysis of homatropine methylbromide in pharmaceutical formulations was developed. This method is based on the formation of a picric acid-quaternary ammonium complex, which is adsorbed on acid-washed diatomaceous earth in alkaline media followed by on-column chloroform extraction. The picrate complex is measured spectrophotometrically at 365 nm. The method was selective for homatropine methylbromide in that there was no interference from its major hydrolytic decomposition products, tropinium methylbromide and mandelic acid.

Automated analysis of warfarin sodium tablets

An automated procedure was developed for the determination of warfarin sodium by following the steps of the manual USP procedure. The automated procedure is applicable to single tablets and composites of 20 tablets at different tablet concentrations. Sensitivity, precision, accuracy, and reproducibility are equivalent to the manual USP procedure. Sensitivity was approximately 15 mug/ml, with a coefficient of variation of 0.711%.

Sinusitis of the maxillary antrum

Twenty-four adults with clinical evidence of sinusitis were studied by 65 needle punctures of the maxillary antrum. Fourteen of 15 sinuses with normal transillumination and 19 of 26 that were dull had normal aspirates, whereas 24 of 24 that were opaque had abnormal aspirates (P less than 0.001). Marked mucosal thickening as determined radiologically (Water's view) was associated with abnormal aspirates whereas lesser mucosal thickening was not (P less than 0.001). In acute sinusitis, there was a strong correlation between high aspirate leukocyte counts (greater than 1000 per cubic millimeter) and infection as manifested by bacterial titers of greater than 10(5) per milliliter or the isolation of virus fungus (P greater than 0.001). Anterior-nasal-swab cultures correlated poorly with direct aspirate culters. Organisms frequently recovered from the sinus included Haemophilus influenzae, Strepto coccus pneumoniae, and anaerobic bacteria. Rhinovirus was recovered twice. Antibiotics were usedful in patients with acute sinusitis if the organism was sensitive in vitro (P less than 0.001).