Biomedical subjects

R Fresco

Publications and source records attributed to R Fresco.

10 recordsLinked to original sources

PubMed1992

Liposome-encapsulated hemoglobin processing methods.

An effective and safe red blood cell substitute is being developed based on double emulsion/evaporation techniques followed by high pressure homogenization to form liposome-encapsulated hemoglobin (LEH). Formulations are made up of hydrogenated phosphatidylcholine (PC, soy or egg), cholesterol, phosphatidylinositol (PI), and alpha-tocopherol in a molar ratio of 1:1:0.2:0.02, respectively. Resulting LEH-encapsulated hemoglobin (Hb) concentrations are greater than 80% of precursor Hb solutions. Met-Hb generation accompanying LEH processing appears to be small with only a 3% increase for encapsulated over precursor. These results correspond to an oxygen content for an LEH suspension sample (50% by volume LEH) of 15 volume% oxygen. Oxygen affinity and cooperativity values for LEH suspensions appear to be near the normal values expected for whole blood. The viscosity of LEH suspension samples (50% by volume LEH in phosphate-buffered saline containing 7.5 wt% albumin) were slightly higher than that of whole blood. The effect of shear rate on leakage of encapsulated Hb from LEH was small, i.e. 0.5% or less. Nearly total isovolemic exchange transfusion using a cannulated rat model demonstrates efficacy of LEH suspension samples. There appears to be no difference in rat internal organ weights between rats exchanged with control compared to rats exchanged with LEH. Circulation half-life following 50% isovolemic exchange-transfusion is about 15 to 18 hours.

Animals↗

PubMed1991

The effect of chronic renal insufficiency on cyclosporine nephrotoxicity.

Despite cyclosporine's efficacy in preventing rejection, its use has been hampered by nephrotoxicity. Questions remain concerning its application in patients with decreased renal function. The purpose of this study was to 1) establish a reliable animal model with chronic renal insufficiency (CRI) to study cyclosporine (CyA) nephrotoxicity, and 2) compare the long-term (50 day) severity of CyA nephrotoxicity in CRI versus normal animals. Fischer 344 rats were divided into six groups (15 to 22 each). In three groups, CRI was induced by a 5/6th nephrectomy (three groups were sham operated). After three wks., daily i.p. injections of olive oil, CyA at five mg./kg., or CyA at 30 mg./kg. daily were administered. Serum and urine were collected at 10 day intervals for the determination of biochemical indices of renal function. Animals were sacrificed after 50 days of treatment and renal histology was evaluated by light and electron microscopy. Chronic CyA treatment was well tolerated by both intact and CRI rats, suggesting that this is a reliable model for long-term CyA toxicity studies. CyA decreased renal function at day 50 in both CRI and intact animals. CRI of mild to moderate degree had little effect on the biochemical and histological indices of CyA induced nephrotoxicity. CRI does appear to potentiate the metabolic toxicity that occurs after chronic treatment with high dose CyA.

Acetylglucosaminidase↗

PubMed1991

Failure to confirm the presence of a retrovirus in cultured lymphocytes from patients with Kawasaki syndrome.

We and others previously reported DNA polymerase activity in culture supernatants of peripheral blood mononuclear cells from patients with acute Kawasaki syndrome (KS). In the present study, we further characterized the previously detected polymerase activity and attempted to confirm its presence in cultured peripheral blood mononuclear cells from additional patients with KS. Characterization experiments indicated that the polymerase activity was typical of a DNA-dependent DNA polymerase rather than viral reverse transcriptase. Peripheral blood mononuclear cell cultures from 17 additional KS patients were negative for reverse transcriptase activity in three laboratories. Our findings do not provide support for a retroviral etiology of KS. Further studies should continue to focus on infectious agents in efforts to elucidate the etiology of KS.

Cells, Cultured↗

PubMed1978

Malacoplakia of the endometrium, a probable cause of postmenopausal bleeding.

A 60-year-old woman, 20 years post-menopausal, who had deforming rheumatoid arthritis of 7 years' duration and Sjögren's syndrome of 1 year's duration, had had postmenopausal bleeding for a month prior to admission to the hospital. A diagnosis dilatation and curettage was interpreted as showing acute suppurative endometritis. The patient was discharged, only to have recurrent vaginal bleeding. She was readmitted five weeks later, at which time results of another dilatation and curettage were interpreted as showing xanthromatous endometritis. Total hysterectomy with bilateral salpingo-oophorectomy was done. Examination of Epon-embedded endometrium 1 micrometer thick by light microscopy and subsequently by electron microscopy disclosed intracellular bacilliform organisms within phagolysosomes of atypical histiocytes, lamellar bodies, and various developing stages of calcospherites, Michaelis-Gutmann bodies. The curettings were then received and classic Michaelis-Gutmann bodies were identified in periodic acid--Schiff-stained sections.

Endometritis↗

PubMed1978

[Psychological factors in the etiology of cancers: methodological problems (author's transl)].

There is a multiplicity of etiological factors in human cancer; psychic factors are probably neither the most important nor the most constant. Nonetheless, owing to the potential infinity of psychological variables, it is necessary to formulate hypotheses in an operational manner. The casuistic method allows a thorough clinical study of objective events, of the manner in which the patient lives them and, especially, of what they mean to him. Such an approach, however, has shortcomings which must be accepted: it cannot administer proof of the hypotheses it advances. The superiority of prospective methods over retrospective methods seems indisputable for there is no evidence that personality traits are not modified by the fatal threat of a serious illness. This criticism also holds for the modified retrospective methods, the so-called predictive methods. Research focussed on particular cancers with a study of limited psychological variables seems desirable.

Humans↗

PubMed1977

[Role of acoustic stress on the development of polyoma tumors in immunized golden hamsters].

An acoustic stress increases the metastatic spread of polyoma virus-induced tumors in syrian Hamsters. To try to elucidate the mechanism of this action, we studied the effect of stress on the protection afforded by the virus against tumour challenge. Exposure to ultrasonics during the immunization period markedly decreased the protective effect of the virus.

Acoustic Stimulation↗

PubMed1977

Mediastinal paraganglioma causing spinal cord compression.

An invasive paraganglioma of the posterior mediastinum caused spinal cord compression in a 31 year old women. Electron microscopic examination of the paraganglioma invading the epidural space revealed numerous dense-cored granules in the cytoplasm of the tumour cells. We are reporting this case to present the ultrastructure of mediastinal paraganglioma, and to call attention to an unusual cause of spinal cord compression.

Adult↗

PubMed1977

Proliferative glomerulonephritis in monoclonal gammopathy.

A 62-year-old white male suffering from plasmacytosis with monoclonal gammopathy developed gastrointestinal bleeding, microscopic hematuria, proteinuria and progressive azotemia. A renal biopsy demonstrated capillary wall thickening, mesangial hyperplasia, crescent formation and subepithelial humps. Serum immunoglobulin analysis showed IgG of lambda type. Serum complement, ANA, ASO titer and cryoglobulin were normal. It is suggested that proliferative glomerulonephritis with subepithelial humps should be added to forms of renal pathology that can be seen in plasma cell dyscrasias.

Basement Membrane↗

PubMed1976

Thermal unfolding of yeast glycine transfer RNA.

In the present investigations the molecular unfolding of yeast tRNA(Gly) has been studied by a combination of nuclear magnetic resonance spectroscopy, melting techniques, and relaxation kinetics. From these studies the following pathway of unfolding was found. In a coupled melting transition the tertiary, the DHU, and the anticodon structure are disrupted. This is followed by the melting of the acceptor arm, while the T psi C arm, which only contains G-C pairs, melts out last. Interestingly, during the first melting transition a new structure not belonging to the original cloverleaf structure is formed. The thermodynamic and kinetic parameters of the melting transitions were determined and are discussed in relation to earlier work. The present nuclear magnetic resonance (NMR) experiments as well as earlier studies show that the ring current calculations based on the cloverleaf structure provide a good first-order interpretation of the NMR spectra of tRNA.

Base Sequence↗

PubMed1976

Viruslike particles in granulomatous angiitis of the central nervous system.

Neuropathologic examination of the brain of a 67-year-old woman with a 5-month history of progressive multiple neurologic deficits showed granulomatous angiitis of the small parenchymal and leptomeningeal blood vessels of the brain and spinal cord. Electron microscopy of formalin-fixed brain disclosed intranuclear viruslike particles resembling herpesvirus. Although definitive proof cannot be established without further virologic tests, this previously unreported finding suggests that some cases of granulomatous angiitis of the central nervous system may result from viral infection.

Aged↗