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Biomedical subjects

F Siegel

Publications and source records attributed to F Siegel.

13 recordsLinked to original sources
PubMed1995

Neither whole inactivated virus immunogen nor passive immunoglobulin transfer protects against SIVagm infection in the African green monkey natural host.

Attempts to protect against infection with simian immunodeficiency virus (SIV)mac grown in rhesus peripheral blood mononuclear cells (PBMCs) using whole inactivated virus immunogen or passive transfer of antibody have so far universally failed. However, such experiments have succeeded in the closely related human immunodeficiency virus (HIV)-2/cynomolgus system. To determine whether the failure in the SIVmac system is typical of primate lentiviruses we performed vaccination and passive transfer experiments using SIVagm (genetically distinct from SIVmac and HIV-2) in the natural African green monkey (AGM) host. To maximize the chances of success, both immunogen and challenge material were prepared using the molecular SIVagm3 clone. Two AGMs were immunized four times with whole inactivated SIVagm3 in RIBI adjuvant and two received intravenously a high dose of immunoglobulin (Ig) purified from a mixture of plasma from AGM, either naturally infected or infected with the homologous SIVagm3 clone. All were challenged with 20 median minimum infective doses of the SIVagm3 grown in AGM PBMCs and previously titrated in AGMs. Despite a strong humoral immune response in all monkeys at the time of challenge, including measurable neutralizing and antibody-dependent cell-mediated cytotoxicity antibodies, none were protected from infection.

Amino Acid Sequence↗
PubMed1992

Placebo-controlled efficacy study of hepatitis A vaccine in Valdivia, Chile.

A placebo-controlled, double-blind study on the efficacy of a hepatitis A vaccine (SmithKline Beecham Biologicals) was started in a region of Chile in September 1990, using hepatitis B vaccine as control. A total of 260 healthy children, 6-15 years of age, negative for antibody to hepatitis A virus (anti-HAV), antibody to HAV immunoglobulin M (IgM), hepatitis B surface antigen, and antibody to hepatitis B surface and core antigens by ELISA tests within 7 days before vaccination, were randomly assigned to two study groups: 128 children received the vaccine with a yellow label (group 1), and 132 children the vaccine with an orange label (group 2) at months 0, 1 and 6. Blood for serology and transaminase determination was drawn at months 1, 2, 6, 7 and 12. Both vaccines were tolerated equally well and no serious side effects were seen. In group 1 (presumed hepatitis A vaccine group), anti-HAV was detected (20% inhibition was used as the cut-off level) in 122 of 128 children (95.5%) tested at month 1, in 126 of 127 (99.2%) at month 2, in 126 of 127 (99.2%) at month 6 and in 126 of 126 (100%) at month 7. One anti-HAV seroconversion seen at month 1 was associated with presence of anti-HAV IgM and therefore probably represents HAV infection. Geometric mean anti-HAV concentration of the other children was 128, 342, 214 and 2301 mIU/ml at months 1, 2, 6 and 7, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Treatment of non-variceal upper digestive hemorrhage with endoscopic thermocoagulation].

Over a year period, 60 of 172 patients presenting with upper gastrointestinal bleeding were treated by endoscopic thermocoagulation. Entry criteria included active bleeding (pulsatile or oozing), a visible vessel, sentinel clot or the presence of a pigmented protuberance at the ulcer crater. Hemostatic therapy was performed using the heat probe. The physical status and risk of the patients was estimated according to the ASA classification. Hemostasis was obtained in 17 of 21 patients with pulsatile bleeding (81%), 30 of 30 patients with oozing (100%) and 18 of 18 patients with a visible vessel or a pigmented protuberance in the lesion (100%). Three patients, older than 70 years of age, died. All had pulsatile bleeding from a deep ulcer located at the posterior-inferior wall of the duodenal bulb. They were classified as ASA III (n = 1) or IV (n = 2) with significant concomitant illness. These results suggest that endoscopic thermocoagulation is an effective treatment of active upper gastrointestinal bleeding, especially useful in a group of high risk patients.

Adult↗
PubMed1992

B-cell epitope mapping of the entire SIVagm envelope glycoprotein including fine mapping of immunogenic regions.

To allow the precise definition of the anti-lentiviral immune response in the natural host and to facilitate the development of an alternative animal model for vaccine development, we are identifying the immunogenic domains of SIVagm proteins. First, a total of 173 synthetic 15-mer peptides with an overlap of 10 amino acids were produced spanning the entire envelope glycoprotein of the molecular clone SIVagm3. These peptides were used as antigen in enzyme-linked immunosorbent assays for identifying regions recognized by antibodies from naturally infected African green monkeys and monkeys infected with a molecular clone. Regions corresponding to the HIV-1 V3, the transmembrane protein (TMP) "Gnann peptide", and the C-terminal area of the outer envelope protein were shown to be immunodominant. These regions were re-synthesized as 15-mer peptides with an overlap of 14 amino acids and used to precisely map the epitopes recognized. Sera from 93 captive and 61 wild animals were tested by SIVagm-specific Western blot (WB) and for ELISA reactivity against the immunodominant TMP peptide. One hundred percent (76/76) of the WB-positive captive animals and 98% (41/42) wild WB-positive animals also reacted against the peptide. In contrast, only 62% of the WB-positive sera reacted with the "V3" epitope and 46% with the gp130 C-terminal epitope.

Amino Acid Sequence↗
PubMed1989

The effect of ultrasound on the in vitro penetration of ibuprofen through human epidermis.

The objective of this study was to develop an in vitro method to investigate the effect of ultrasound on the in vitro absorption of ibuprofen from a propylene glycol/water vehicle through human epidermis. A diffusion cell was modified so ultrasound could be applied to the vehicle and skin. Since ultrasound can increase the temperature underneath the area of application, control representing temperature effects ran concurrently to the ultrasound experiment. The results demonstrate that ultrasound can increase the penetration of ibuprofen through human skin. This increase in diffusion was greater than for controls where an equivalent increase in temperature was utilized. The results also indicate that evaporation of vehicle components may alter the skin/vehicle partition coefficient, decreasing the effects of ultrasound on the penetration of ibuprofen through the skin.

Adolescent↗
PubMed1989

[Morphology and vital reaction in heart injuries].

In injuries of the heart after action of blunt and sharp force as well as gunshot injuries, in particular the histological findings are also important with regard to survival time and capacity of action. Single observations have given rise to the impression that vital reactions occur here earlier (thrombocyte aggregates, leukocytic emigration, formation of clots) than is the case in other organs. Systematic investigations of 48 cases amongst 373 heart injuries (3.9% of 11,342 autopsies, from 1983 to the last quarter of 1988) from the Institute for Forensic Medicine of the University of Munich as well as occasional cases from the Institute of Forensic Medicine of the Free University of Berlin did not show any leukocytic reactions in light microscopy with no or short survival time. In electron microscopic terms, leukocytic reactions, thrombocyte aggregates or deposits of fibrin were not to be discerned even in heart injuries which were survived for a short time. However, high-grad contractions and condensations of the muscle fibers with filamentous evaginations into which the mitochondria were pressed were shown characteristically. These alterations indicated a vital process, but they may possibly also occur even in the earliest supravital phase. In a total of 25 cases with confirmed survival time between 30 minutes and five days, cell reactions were shown which largely corresponded to the familiar time course. A prematurely occurring reaction was not to be observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Survival↗
PubMed1988

Percutaneous sonographic needle aspiration biopsy of endoscopically negative gastric carcinoma.

We report here the use of ultrasound-guided percutaneous fine needle aspiration gastric biopsies in three patients with endoscopically negative biopsies. Two men, ages 60 and 64, and one woman, age 64, with signs and symptoms of weight loss, abdominal pain, and early satiety, had barium contrast studies suggestive of thickened gastric walls of the antrum and cardia, yet multiple endoscopic biopsies were negative for malignancy. Using real time sector B-scan ultrasonography, percutaneous fine needle aspiration biopsy retrieved signet cell carcinomatous cytologic material in all three patients. No complications were noted. In patients with clinical and radiographic findings compatible with an infiltrative process but negative endoscopic biopsies, in whom sonography can identify a thickened stomach wall, we suggest that percutaneous fine needle aspiration biopsy be attempted.

Adenocarcinoma, Mucinous↗
PubMed1983

A problem-oriented precepting method.

An organized method of clinical precepting may increase preceptor effectiveness. Problem-oriented precepting is an organized teaching method directed not only at achieving high-quality care for the presented patient, but also at solving the problems of the medical provider that block that goal. The precepting method consists of the following steps: (1) identify initial impressions, (2) confirm or refute these impressions, (3) identify the problem, (4) develop teaching goals, (5) devise methods to achieve these goals, and (6) evaluate outcome. The use of this step-by-step process permits earlier definition of resident problems, which can improve the resident's problem-solving ability.

Adult↗
PubMed1979

Impeded cerebellar development and reduced serum thyroxine levels associated with fetal alcohol intoxication.

Pregnant albino rats were placed on a complete liquid diet (Ensure) containing either 9% ethanol or an isocaloric amount of sucrose between the third and twentieth day of gestation. The pups born to these rats were sacrificed either day 11 or day 14 postnatum and morphometrical, histological and biochemical analyses were done on their cerebellums and cerebrums. Pups that were exposed to ethanol in utero had significantly smaller body weights, cerebrums and cerebellums than pair-fed controls. The cerebellar mass was reduced by 10% and the cerebral weight by 3% in the pups exposed to alcohol when body weights were normalized to that of pair-fed controls. Cerebellar aspartyl aminotransferase (EC 2.6.1.1) activity was reduced at day 11 and 14 in ethanol treated pups compared with controls. Serum T4 levels were also reduced in the ethanol treated group. Histological analyses revealed that the external granule cell (EGC) layer of ethanol treated pups was significantly thicker at 11 and 14 days postnatum than that of pair-fed control pups. Cerebellar ornithine decarboxylase (ODC, EC 4.1.1.17) activity was higher at day 11 in the ethanol treated pups than in controls. The reduced mass, AAT activity, T4 serum levels and the increased thickness of the ECG layer indicate a delayed or impeded maturation of cerebellum in ethanol treated pups. These data are considered from the viewpoint that ethanol, other drugs such as methadone and prenatal stress (malnutrition) may cause delayed cerebellar maturation by reducing serum T4 levels in the early postnatal period (day 5-14).

Alcohol Drinking↗