Antigenic differences associated with genetically distinct Pneumocystis carinii from rats

Pneumocystis carinii is a family of organisms found in a wide variety of mammalian lungs. In immunocompromised hosts, the organisms are able to produce an oftentimes fatal pneumonia. The existence of distinct types of Pneumocystis populations is strongly supported by antigenic and genetic evidence. In the present study, we assessed the antigenic profiles of two genetically distinct Pneumocystis carinii populations, P. carinii f. sp. carinii and P. carinii f. sp. ratti, as well as two types of P. carinii f. sp. carinii defined by electrophoretic karyotyping (forms 1 and 2). The separated and blotted proteins of the organism preparations were probed with four monoclonal antibodies (MAbs) generated to the major surface glycoproteins of rat-derived P. carinii, one anti-human P. carinii MAb, and two polyclonal antisera made with rat-derived P. carinii as the immunogen. Differences in reactivities between the P. carinii f. sp. carinii and P. carinii f. sp. ratti preparations were detected with two of the MAbs, and both of the rat P. carinii polyclonal antisera in the 45- to 55-kDa molecular mass range, but not with the human P. carinii MAb. The reactivities of the 16 P. carinii f. sp. carinii preparations were the same with two exceptions. Two preparations of form 1 showed strong reactivity with the anti-MSG MAb RA-C11. The ratios of cyst forms to trophic forms evaluated by microscopy were not associated with any of the differences observed in the antigenic profiles. The antigenic differences between P. carinii f. sp. carinii and P. carinii f. sp. ratti are consistent with the distinction of these two populations made by molecular genetic techniques, while the two differences detected among the P. carinii f. sp. carinii preparations suggest the organism may be able to modulate antigenic epitopes. The use of immunoblotting to differentiate infecting organism populations and assess antigenic modulation holds promise for future epidemiologic studies.

Expression of apple 1-aminocyclopropane-1-carboxylate synthase in Escherichia coli: kinetic characterization of wild-type and active-site mutant forms

The pyridoxal phosphate-dependent enzyme 1-aminocyclopropane-1-carboxylate synthase (ACC synthase; S-adenosyl-L-methionine methylthioadenosine-lyase, EC 4.4.1.14) catalyzes the conversion of S-adenosylmethionine (AdoMet) to ACC and 5'-methylthioadenosine, the committed step in ethylene biosynthesis in plants. Apple ACC synthase was overexpressed in Escherichia coli (3 mg/liter) and purified to near homogeneity. A continuous assay was developed by coupling the ACC synthase reaction to the deamination of 5'-methylthioadenosine by adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4) from Aspergillus oryzae. The enzyme is dimeric, with kcat = 9s-1 per monomer and Km = 12 microM for AdoMet. The pyridoxal phosphate-binding site of ACC synthase appears to be highly homologous to that of aspartate aminotransferase, suggesting similar roles for corresponding residues. Site-directed mutagenesis of Lys-273, Arg-407, and Tyr-233 (corresponding to residues 258, 386, and 225 in aspartate aminotransferase) and kinetic analyses of the mutants confirms their importance in the ACC synthase mechanism. The Lys-273 to Ala mutant has no detectable activity, supporting the identification of this residue as the base catalyzing C alpha proton abstraction. Mutation of Arg-407 to Lys results in a precipitous drop in kcat/Km and an increase in Km for AdoMet of at least 20-fold, in accordance with its proposed role as principal ligand for the substrate alpha-carboxylate group. Replacement of Tyr-233 with Phe causes a 24-fold increase in the Km for AdoMet and no change in kcat, suggesting that this residue plays a role in orienting the pyridoxal phosphate cofactor in the active site.

Determination of pefloxacin concentration in mesenteric lymph nodes by high-performance chromatography

Ten patients who had undergone laparotomies for different abdominal pathological conditions were studied to determine the levels of pefloxacin in mesenteric lymph nodes. Each patient was given 400 mg of oral pefloxacin every 12 h for the 3 days prior to surgery. Drug levels in tissue were determined by high-pressure liquid chromatography (reverse phase); the mean +/- standard deviation was 17.1 +/- 11.9 micrograms/g, with a range of 2.12 to 36.6 micrograms/g. This indicates an adequate pefloxacin concentration in lymph nodes and makes the drug a good option for the treatment of conditions in which lymph nodes act as an infection-promoting and/or relapse-favoring factor.

Conventional and color Doppler transvaginal sonography in gynecologic infertility. Current clinical applications

TVS affords accurate follicular monitoring and guidance for follicular aspiration. The role of TVS in assessing the adequacy of the endometrium is still undergoing investigation. Our studies suggest that there is a statistically significant difference in the pregnancy rate when the endometrium has a multilayered appearance. Infertility patients who successfully achieve pregnancy should be monitored with TVS because of a higher incidence of ectopic pregnancy, anembryonic gestation, and spontaneous abortion. TVS has a secondary role in evaluating certain uterine malformations and tubal disorders. With TV-CDS it is also possible to evaluate physiologic parameters such as adnexal and uterine blood flow. The role of TV-CDS in the anatomic and physiologic evaluation of early pregnancy is now being established.

A prospective, randomized, double-blind, crossover study to compare the efficacy and safety of chronic nifedipine therapy with that of isosorbide dinitrate and their combination in the treatment of chronic congestive heart failure

We performed a prospective, randomized, double-blind, crossover study to compare the efficacy and safety of vasodilation with the calcium entry blocker nifedipine with that of isosorbide dinitrate (ISDN) and their combination as treatment for heart failure. Twenty-eight patients with New York Heart Association Functional class II or III chronic heart failure due to left ventricular systolic dysfunction were studied. All patients were maintained on a constant dose of digitalis and diuretics throughout the study. Eight weeks of therapy with nifedipine alone or in combination with ISDN resulted in a significantly higher incidence of heart failure deterioration necessitating hospitalizations and/or additional diuretics. Twenty-four percent of patients required hospitalization during nifedipine therapy and 26% required hospitalization during nifedipine-ISDN combination therapy in comparison to 0% requiring hospitalization during ISDN therapy alone. The total number of heart failure-worsening episodes was nine among patients on nifedipine, three among patients on ISDN (p less than 0.09 versus nifedipine), and 21 among patients on nifedipine-ISDN combination (p less than 0.001 versus nifedipine, p less than 0.0001 versus ISDN). Premature discontinuation of drug administration due to clinical deterioration or other side effects occurred in 29% of patients during nifedipine therapy, 5% of patients during ISDN therapy (p = 0.05 versus nifedipine), and 19% of patients during the combination therapy. A comparison of eight patients who demonstrated clinical deterioration on nifedipine with the remainder of the patients demonstrated no significant difference in left ventricular ejection fraction (0.24 +/- 0.06 versus 0.23 +/- 0.07) or maximal oxygen uptake during exercise (13 +/- 3 versus 14 +/- 2 ml/kg/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Central and renal hemodynamic effects of a new agonist at peripheral dopamine- and beta-2 adrenoreceptors (dopexamine) in patients with heart failure

The effect of dopexamine, a new dopamine analogue, on central and renal hemodynamics was evaluated in nine patients with chronic, congestive heart failure caused by severe left ventricular (LV) systolic dysfunction. The administration of the maximally tolerated dose (7.2 +/- 4 micrograms/kg/min) resulted in a significant increase in cardiac index from 1.9 +/- 0.4 L/min/m2 to 2.6 +/- 0.9 L/min/m2 (p less than 0.05). This increase in cardiac index was largely a result of increase in heart rate (from 88 +/- 20 beats/min to 104 +/- 24 beats/min, p less than 0.05), because stroke volume index demonstrated only a small change (from 23 +/- 10 ml/m2 to 27 +/- 11 ml/m2, p not significant) in spite of a significant fall in systemic vascular resistance from 1992 +/- 717 dynes.sec.cm-5 to 1361 +/- 524 dynes.sec.cm-5 (p less than 0.05) and diastolic blood pressure (from 89 +/- 15 mm Hg to 80 +/- 17 mm Hg, p less than 0.05). No change was seen during dopexamine infusion in systolic blood pressure, right and left ventricular filling pressures, and LV stroke work index. Both renal blood flow and glomerular filtration rate were impaired at baseline in most patients. Dopexamine administration resulted in a significant increase (2x coefficient of variation) in renal blood flow in two patients only. Mean values of both renal blood flow and glomerular filtration rate did not show significant change (485 +/- 183 ml/min vs 563 +/- 221 ml/min and 89 +/- 39 ml/min vs 93 +/- 34 ml/min, respectively, p not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

A nontoxic adjuvant treatment for advanced head and neck cancer

A variety of adjuvant chemotherapy programs have been described for advanced head and neck cancer. The protocol described herein is nontoxic and particularly appropriate for patients with advanced tumors who cannot, because of severe pulmonary disease, tolerate bleomycin sulfate. Eighty percent of patients treated with this combination responded with more than 50% tumor shrinkage. Chemotherapy was followed by either surgery, radiation therapy, or both. Long-term control with this combined modality therapy was better in oral cavity and oropharyngeal lesions than in tumors from the hypopharynx.

The role of estrogens in mastopathy and mammary cancer in perimenopausal women

Fibrocystic disease of the breast (FCD) is an exaggeration of the normal physiologic response to cyclic estrogen and progesterone stimulation. The disorder can persist, with much less severity, in the menopausal woman. Whether FCD predisposes to mammary cancer remains moot. A new steroidal agent, danazol, can eliminate nodosities in the majority of women with FCD. Thermography may identify women who are at greater risk because of increased heat production. Mammography should be employed in women with persistently abnormal thermograms, even though no suggestive breast masses are palpable. Needle biopsy or surgical biopsy should be undertaken whenever a firm indurated mass is palpated, regardless of negative findings with a thermogram or mammogram. In a series of 1548 women treated for 10,715 women-years, the incidence of breast cancer after prolonged estrogen therapy was not increased. Although estrogens and prolactin have been incriminated in the etiology of mammary cancer, no hard facts exist to confirm such allegations.

Fibrocytic breast disease: current status of diagnosis and treatment

Improved diagnostic procedures and use of a new steroidal agent, danazol (Danocrine), should reduce the need for surgical intervention in fibrocystic breast disease. Thermography, a non-invasive procedure that may be used with impunity, may help identify women at high risk. Mammography, which is useful in revealing malignancy in an early stage, should be done in women with tow consecutive abnormal thermograms. Biopsies should be performed, however, on suspicious, firm, irregular masses, regardless of results on thermography or mammography. Use of danazol may be advantageous not only in ameliorating pain and eliminating nodosities, but also in guiding the surgeon to the nodule that is unresponsive to treatment and therefore should be evaluated by biopsy.

Observations on the antigenicity and clinical effects of a candidate antipregnancy vaccine: beta-subunit of human chorionic gonadotropin linked to tetanus toxoid

Observations on the antibody response and clinical effects of injection of purified beta-subunit of human chorionic gonadotropin covalently linked to tetanous toxoid were made in 15 healthy young women who had previously undergone tubal ligation. Antibodies detectable by radioimmunoassay were found in 14 of the women. Clinical surveillance and immunologic, hematologic, and biochemical tests indicated excellent local and systemic tolerance to the antigen. No significant adverse effects on menstrual function, endocrine status, or health were found.

The cholinergic pathway to cerebral blood vessels. I. Morphological studies

The application of cobalt chloride to the peripheral cut end of the greater superficial petrosal nerve (g.s.p.n.) in rats revealed that only a few fibers in the plexus of nerves on the adventitial surface of the internal carotid artery were in axonal continuity with the g.s.p.n. A similarly small contribution of cholinergic fibers to cerebral blood vessels from this nerve was suggested by the observation that section of the g.s.p.n. resulted in an insignificant reduction in the density of the AChE-staining plexus in the internal carotid and cerebral arteries and in the incidence of at most 2% degenerate terminals of those observed on the middle cerebral artery. Alternative explanations of the results are discussed: that the AChE-staining fibers are postganglionic, that the time course for degeneration is unusually slow and that non-cholinergic fibers stain non-specifically for AChE. It is concluded that a cholinergic dilator pathway is most probably carried by the g.s.p.n. but that it is not unique.