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Biomedical subjects

P Frost

Publications and source records attributed to P Frost.

At least 163 records · Page 9Linked to original sources
PubMed1980

Catecholamine cell groups of the cat medulla oblongata.

The distribution of catecholamine-containing cells within the cat medulla oblongata has been studied using formaldehyde-glutaraldehyde fluorescence histochemistry. The diffuse ventrolateral cells (A1) were scattered around but not within the lateral reticular nucleus and no cells were found dorsal to the inferior olivary nucleus. The dorsomedial (A2) cells were scattered within the nucleus tractus solitarius with an occasional cell within the dorsal motor nucleus of the vagus. No A2 cells were found within or ventral to the hypoglossal nucleus. This description contrasts in several respects with a recently published atlas of the catecholamine-containing neurons in the cat medulla.

Animals↗
PubMed1980

Immune regression of visceral metastases in athymic mice. Correlation of "low-level" in vitro cell-mediated cytotoxic reactions with allograft rejection in vivo.

The MDAY-D2 tumor of DBA/2 origin metastasizes widely and predictably in syngeneic DBA/2 mice, as well as in allogeneic athymic mice. BALB/c mice, which are H-2 compatible with MDAY-D2, reject the tumor based on non-H2 histocompatibility antigens. This rejection corresponds directly with the generation of a "low-level," in vitro, cell-mediated cytotoxic response in ipsilateral peripheral lymph nodes and spleen. Production of cytotoxic antibody also occurs during tumor rejection. Previous work has demonstrated the effectiveness of adoptively transferred, sensitized BALB/c lymphocytes in eliminating preexisting visceral metastases in BALB/c athymic mice. The present study shows that in this model the complete regression of H-2-compatible allografts, in the form of preexisting metastases, correlates directly with the ability of adoptively transferred cells to mediate low-level, cell-mediated cytotoxicity in vitro. Both graft rejection in vivo and cell-mediated cytotoxicity in vitro are mediated by T cells. Enriched sensitized B cells and anti-MDAY-D2 serum are both incapable of mediating this graft rejection in vivo. Based on these findings, we conclude that relatively weak in vitro cell-mediated cytotoxic responses should not be dismissed as biologically insignificant, for they may be indicative of considerable immune potential in vivo.

Animals↗
PubMed1980

An assessment of factors influencing flexibility of human fingernails.

A new instrument has been developed and used to determine the effect of various materials on nail flexibility. It repeatedly flexes longitudinal nail sections through 90 degrees and records the number of flexions required to fracture each section. Immersion in water or a phospholipid-water preparation (PLW) greatly increases the flexibility of untreated and lipid extracted nails; immersion in mineral oil does not. Nail flexibility is directly related to the duration of their immersion in water. During water immersion, nail weight increases by 22% of its original weight within 2 h, and then decreases. The rapid increase in nail flexibility during water immersion is related to nail water content. It is possible to prolong the flexibility of previously hydrated nails by the application of PLW or mineral oil. PLW is more effective than water alone in prolonging flexibility of nails extracted with a mixture of acetone, water and acetic acid.

Biophysics↗
PubMed1980

Retrospective analysis of a modified Goeckerman regimen for the treatment of psoriasis.

The records of all patients treated at Mount Sinai Medical Center of Greater Miami with a modified Goeckerman regimen from 1972 to 1977 were analyzed. When a stringent definition of "clearing" was applied, it was found that approximately half of the patients were cleared of their psoriasis on this regimen and that the time the patients remained clear following treatment averaged 125 days. The mean number of treatments required for clearing was twenty-four which is in the same range as reported for PUVA therapy. For those patients that cleared, this average number of treatments was a more important variable than the time over which the treatments were administered.

Aged↗
PubMed1979

Tar gel-phototherapy for psoriasis. Combined therapy with suberythemogenic doses of fluorescent sunlamp ultraviolet radiation.

To determine the efficacy of suberythemogenic ultraviolet phototherapy in conjunction with administration of a tar gel (SEUV TG), patients with widespread psoriasis were treated by application of a tar gel preparation followed after 12 hours by suberythemogenic doses of fluorescent sunlamp irradiation. In paired comparison studies, therapeutic effects of the following treatments were evaluated: SEUV-TG, a more conventional erythemogenic tar gel phototherapy regimen (modified Goeckerman), the tar gel alone, and SEUV irradiation following application of gel vehicle. Response to therapy was monitored with a severity score system. In patients with psoriasis responsive to phototherapy, smaller quantities of UV energy administered in combination with a tar gel were at least as effective as larger erythemogenic doses. Production of erythema with fluorescent sunlamp radiation does not appear to be necessary to improve psoriasis. Both UV radiation and tar gel have beneficial effects on psoriasis, but the combination is superior.

Adolescent↗
PubMed1979

Efficacy of mycophenolic acid for the treatment of psoriasis.

The efficacy of orally administered mycophenolic acid (MPA), an inhibitor of guanosine monophosphate (GMP) synthesis, for the treatment of psoriasis, was studied in a double-blind fashion. Of twenty-one patients completing the study period, ten of eleven patients treated with MPA had a greater than 25% decrease in severity score compared with only two of ten patients treated with placebo. The placebo group had a slight increase in severity score compared to almost 50% reduction in the average severity score of the MPA-treated group. After termination of the double-blind portion of the study, the placebo group was treated with MPA and showed a 60% decrease in severity score. Adverse effects encountered included anorexia, nausea, vomiting, and diarrhea. One patient had an uncomplicated episode of herpes zoster. Other than a mild decrease hemoglobin, no hematologic toxicity was noted.

Adult↗
PubMed1979

Immune-mediated arrest and reversal of established visceral metastases in athymic mice.

The metastasizing MDAY-D2 tumor of DBA/2 mice disseminates in BALB/c allogeneic athymic nude (nu/nu) mice in a manner identical to that observed in the syngeneic host. Both the kinetics and organ distribution pattern of metastases from s.c. implants of MDAY-D2 are routinely predictable at any given tumor dose. BALB/c heterozygote (nu/+) litter-mates reject MDAY-D2 grafts on the basis of the multiple minor histocompatibility differences that exist between DBA/2 and BALB/c mice. The in vitro cell-mediated cytotoxic response detected in tumor-bearing BALB/c nu/+ mice is "low grade" (isotope release is approximately 40 to 50% by 24-hr 111-indium-8-hydroxyquinoline assay and approximately 6 to 8% by 6-hr 51Cr assay) and yet correlates directly with tumor rejection. BALB/c nu/nu mice can be protected against MDAY-D2 by previous reconstitution with lymphoid cells from normal or MDAY-D2-sensitized BALB/c nu/+ mice. In addition, surgically documented, established visceral metastases in BALB/c nu/nu mice can be arrested and regressed by the adoptive transfer of MDAY-D2-sensitized BALB/c nu/+ spleen cells. This represents one of the few models where established metastases have been immunotherapeutically regressed. As such, the MDAY-D2 BALB/c nu/nu mouse model offers unique advantages for studying the role of the immune system in regulating the metastatic process.

Abdominal Neoplasms↗
PubMed1979

Early surgical management of acute cholecystitis.

Between 1971 and 1977, 361 patients underwent early elective cholecystecomy for acute cholecystitis, and the complications and mortality were studied according to the length of time from admission to operation. A substantially greater proportion of the complications, and the only deaths, occurred in the patients operated upon more than 7 days after admission. The mortality rate was 0.6%. Nine additional high-risk patients underwent cholecystostomy. There were four postoperative deaths in this group, all related to the debilitating underlying conditions. The mortality for the entire series was 1.6%. These results compare favourably with those following delayed elective operations for acute cholecystitis. Early elective operation, using cholecystectomy when possible and cholecystostomy when necessary, is recommended for general use in experienced hands. This practice is safe and sound particularly when the diagnosis is made more certain preoperatively by the use of intravenous cholangiography.

Acute Disease↗
PubMed1979

Effects of emollients on ultraviolet-radiation-induced erythema of the skin.

Several commonly used emollients were studied as to their effectiveness in absorbing and filtering erythema-causing ultraviolet radiation in the 280 to 315 nm range (UVB). Planter's Peanut Oil (Standard Brands) and Mazola Corn Oil (Best Foods Inc) had no effect; Alpha Keri Bath Oil (Westwood Pharmaceuticals), mineral oil, and Johnson's Baby Oil (Johnson & Johnson Co) had minimal effects. Vaseline Petroleum Jelly (Chesebrough-Ponds Inc), petrolatum, and hydrophilic ointment substantially reduced the erythema that was induced by exposure to low doses of UVB radiation. Therefore, these emollients may interfere with the therapeutic effects of the ultraviolet radiation component of the Goeckerman treatment when it is administered in low doses to patients with psoriasis.

Dermatologic Agents↗
PubMed1978

Isotope-release cytotoxicity assay with the use of indium-111: advantage over chromium-51 in long-term assays.

The adaptation of indium-111-oxine (also known as 8-hydroxyquinoline) (111In Ox) chelate for long-term (18-48 hr) isotope-release assays of cell-mediated cytotoxicity (CMC) and its advantages over the use of 51 Cr are described. Labeling of DBA/2 P815 mastocytoma cells with 111InOx resulted in the incorporation of as many as a million counts per minute in 10(5) cells with no reduction in cell viability. 111InOx labeled both mouse and human tumor cells. 111InOx, like 51Cr, primarily labeled cytoplasmic constituents; up to 80% of the label existed in a releasable form. 111InOx was quantitatively released from labeled P815 in response to specifically sensitized C57BL/6 lymphocytes. The high labelling efficiency of 111InOx offered a significant advantage over 51Cr in 18- to 48-hour assays for CMC by reducing the counting error and thus making the assay more precise. Because of its higher labeling efficiency, 111InOx can be used in microcytotoxicity assays. 111InOx has the added advantage of a lower spontaneous release in culture than 51Cr. This feature of 111InOx also makes the calculation of specific isotope release more accurate than that achieved with 51Cr in long-term cytotoxic assays.

Animals↗
PubMed1978

Epstein-Barr virus infections in Brazil. II. Hodgkin's disease.

Sixty-seven cases of Hodgkin's disease (HD) occurring in São Paulo, Brazil, were studied. Males with HD predominated over females 2.3 to 1. Sixty-six percent of the cases occurred in patients under 30 years of age, 31.7% under 20 years of age, and only 7.5% after 50 years of age. Lymphocyte predominance and mixed cellularity histologic types were most common in patients less than 15 years old, and nodular sclerosis was most common in the 15- to 19-year-old group. Sera from all patients had antibody to the viral capsid antigen (VCA) of Epstein-Barr virus (EBV). The geometric mean titer (GMT) of VCA antibody with the use of Jijoye cells as antigen was 1:162, and 31.3% of patients had titers of 1:320 or more; in controls, the GMT was 1:67 and 3.8% had titers of 1:320 or more. Similar results were obtained when EB-3 cells were used as antigen. The highest titers occurred in males, in mixed cellularity and lymphocyte depletion forms, and in stage 2 of illness. EBV-specific IgM antibody and heterophile antibody levels were not elevated, but 20.5% of the HD patients had antibody to the early antigen of EBV present in their sera. Antibody levels for herpes simplex virus, cytomegalovirus, rubella, measles, parainfluenza viruses, and papovavirus were not significantly elevated over those in matched controls.

Adolescent↗