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Biomedical subjects

P Pfeiffer

Publications and source records attributed to P Pfeiffer.

At least 109 records · Page 6Linked to original sources
PubMed1990

Clinical and electrodiagnostic findings in breast cancer patients with radiation-induced brachial plexus neuropathy.

The clinical and neurophysiological characteristics of radiation-induced brachial plexopathy (RBP) were assessed in 79 breast cancer patients without signs of recurrent disease at least 60 months after radiotherapy (RT). Clinically, 35% (95% confidence limits: 25-47%) had RBP. Fifty percent (31-69%) had affection of the entire plexus, 18% (7-36%) of the upper trunk only, and 4% (1-18%) of the lower trunk. In 28% (14-48%), assessment of a definite level was not possible. In most, symptoms began during or immediately after RT, thus being without significant latency. Numbness or paresthesias (71%, 52-86%) and pain (43%, 25-62%) were the most prominent symptoms, while the most prominent objective signs were decreased or absent muscle stretch reflexes (93%, 77-99%) closely followed by sensory loss (82%, 64-93%) and weakness (71%, 52-86%). Neurophysiological investigations were carried out in 46 patients (58%). The most frequent abnormalities in patients with RBP were signs of chronic partial denervation with increased mean duration of individual motor unit potentials, and decreased amplitude of compound muscle and sensory action potentials. Nerve conduction velocities were normal.

Adult↗
PubMed1990

Radiation-induced brachial plexus neuropathy in breast cancer patients.

The incidence and latency period of radiation-induced brachial plexopathy (RBP) were assessed in 79 breast cancer patients by a neurological follow-up examination at least 60 months (range 67-130 months) after the primary treatment. All patients were treated primarily with simple mastectomy, axillary nodal sampling and radiotherapy (RT). Postoperatively, pre- and postmenopausal patients were randomly allocated chemotherapy or antiestrogen treatment. All patients were recurrence-free at time of examination. Clinically, 35% (25-47%) of the patients had RBP; 19% (11-29%) had definite RBP, i.e. were physically disabled, and 16% (9-26%) had probable RBP. Fifty percent (31-69%) had affection of the entire plexus, 18% (7-36%) of the upper trunk only, and 4% (1-18%) of the lower trunk. In 28% (14-48%) of cases assessment of a definite level was not possible. RBP was more common after radiotherapy and chemotherapy (42%) than after radiotherapy alone (26%) but the difference was not statistically significant (p = 0.10). The incidence of definite RBP was significantly higher in the younger age group (p = 0.02). This could be due to more extensive axillary surgery but also to the fact that chemotherapy was given to most premenopausal patients. In most patients with RBP the symptoms began during or immediately after radiotherapy, and were thus without significant latency. Chemotherapy might enhance the radiation-induced effect on nerve tissue, thus diminishing the latency period. Lymphedema was present in 22% (14-32%), especially in the older patients, and not associated with the development of RBP. In conclusion, the damaging effect of RT on peripheral nerve tissue was documented. Since no successful treatment is available, restricted use of RT to the brachial plexus is warranted, especially when administered concomitantly with cytotoxic therapy.

Adult↗
PubMed1990

Effect of prophylactic sucralfate suspension on stomatitis induced by cancer chemotherapy. A randomized, double-blind cross-over study.

We have studied whether mouth-swishing with sucralfate, a well-known gastric mucosal protective agent, may be used as prophylaxis against chemotherapy-induced stomatitis. Using radioactively labelled sucralfate we found that 20-30% was still bound to the oral mucosal lining 2 1/2 h after mouth-swishing. Forty patients receiving cisplatin and continuous infusion with 5-fluorouracil (5-FU) for 5 days entered a double-blind placebo-controlled cross-over study. Among 23 evaluable patients a significant reduction (p = 0.04) in an objective score of edema, erythema, erosion and ulcerations was seen during treatment with sucralfate. Patient preference favored sucralfate, but this preference failed to reach statistical significance (p = 0.06). Seven patients were inevaluable for reasons not associated with the study treatment. However, ten patients did not complete the study since the swishing procedure aggravated chemotherapy-induced nausea. An equal rate of non-compliance was seen with sucralfate and placebo. To overcome this problem, the oral medication should have a neutral taste, the solution should not be swallowed after the swishing, which should not be started until the nausea had ceased.

Adult↗
PubMed1990

[Injury-free removal of cemented crowns and bridges].

Seven methods for removing crowns and bridges were studied in in vitro tests. Systems gripping the crowns on both sides led to the best results. Cemented crowns were loosened by ultrasound. All restorations could be removed after an average time of 6 1/2 min ultrasound influence. The increase of temperature in the pulp chamber requires sufficient waterspraying.

Crowns↗
PubMed1990

[Bonding of air-brushed non-noble metal surfaces].

Frequently, bonded restorations are not inserted into the patients' mouths until a few days after air brushing in the laboratory. By that time the reactive bonds of the metal surface may have undergone saturation by air during storage or by saliva components during try-in. This in turn, might result in a loss of bond strength. According to the present in vitro study it is possible to bond NPM alloy restorations with Panavia Ex several days after air brushing with corundum. The bond strength after up to 150 days of storage in water is approx. 25 N/mm2 and thus clearly above the clinical minimum requirements of 10 N/mm2 (internal enamel strength). After contamination with saliva, restorations must be air brushed again before bonding.

Dental Alloys↗
PubMed1990

[Clinical long-term results with bonded bridges].

788 patients with 3-unit resin-bonded bridges were followed up over a time period of up to 5 years after placement. In this multicenter study, the following clinical variables were analyzed: caries, periodontal disease, loss of pulp vitality and the behavior of the dental materials involved were assessed. Adverse findings were rare. More data are needed over a longer period of time to support the present results.

Adhesives↗
PubMed1990

[Solubility of nickel from dental alloys in saliva].

Dental students in the clinical courses of prosthodontics manufactured maxillary cast partial dentures from 6 nickel-containing alloys according to set guidelines. Prior to insertion as well as up to 7 days after insertion resting saliva samples were collected and analyzed for their nickel contents with the aid of atomic absorption spectrometry (AAS) using a graphite tube. 20 min after insertion the salivary nickel levels were above the blank value. After 3 h the salivary nickel levels were as half as high compared to values of 20 min. After 7 days for most alloys they decreased to the starting values again.

Dental Alloys↗
PubMed1989

Differential inhibition of downstream gene expression by the cauliflower mosaic virus 35S RNA leader.

The effect of the 600 nucleotide-long CaMV 35S RNA 5' leader sequence on the expression of downstream genes was analyzed both in plant protoplasts and in vitro. For transient expression studies in protoplasts derived from host and nonhost plants, the bacterial chloramphenicol acetyl transferase (CAT) gene was fused to the initiation codon of ORF VII. The leader sequence reduced CAT expression two- to four-fold in protoplasts derived from three host species, but 10- to 50-fold in protoplasts derived from three different nonhost species. For in-vitro studies the 35S promoter was replaced by the SP6 promoter. The leader reduced in-vitro translation of SP6 transcripts approximately six-fold, indicating that at least part of the inhibition observed in protoplasts is directly due to the interference of the leader sequence with translation. Other steps in gene expression that may also be affected are discussed.

Chloramphenicol O-Acetyltransferase↗
PubMed1989

Intraperitoneal chemotherapy: introduction of a new "single use" delivery system--a preliminary report.

Intraperitoneal administration of chemotherapy in ovarian cancer is currently under investigation. In this preliminary report we introduce the "Veress-needle" as a "single-use" delivery system of intraperitoneal chemotherapy. A total of 22 infusions in 7 patients revealed no major complications, and during 4 infusions only minor side effects were noted. The technique described seems to fulfill the need for a safe, reliable, and acceptable delivery system of intraperitoneal chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Primary carcinoma of the fallopian tube. A retrospective study of patients reported to the Danish Cancer Registry in a five-year period.

Fifty-two patients with carcinoma of the fallopian tube diagnosed and treated during a 5-year period in Denmark were reviewed. The median age of the patients was 60 years. No patients had a preoperative diagnosis. History and clinical findings were similar to previously reported series. Treatment consisted of hysterectomy and bilateral salpingo-oophorectomy, often succeeded by postoperative whole pelvic irradiation. Five-year survival was 37.4%, depending on stage. In stage I+II the survival rates were similar regardless of whether postoperative radiation therapy had been given or not. Little is known about the patterns of spread. The relatively bad prognosis for stages I and II after radical surgery indicates early undetected metastases and the need for more aggressive adjunctive therapy.

Actuarial Analysis↗
PubMed1989

[Conserving silicoater treated surfaces with primers for use in adhesive prostheses].

UNLABELLED: To achieve permanent bond strength to enamel adhesive fixed partial dentures can be coated for example by a SiOx-C-layer followed by a silane primer (Silicoater system). Now and then these resin bonded restorations will be incorporated some days later. The object of this in-vitro-study was to investigate the possibility of preserving metal surfaces treated by the Silicoater system. RESULTS: Metal surfaces coated in the described manner can be preserved by unfilled Bis-GMA-, PMMA-adhesives or a light curing opaquer (PMMA monomer) for later bonding without loss of bond strength. To cure the opaquer a special light curing apparatus is needed.

Adhesives↗
PubMed1989

[Solubility of dental alloys in saliva].

Five dental probationers each of the clinical courses for prosthodontics manufactured maxillary cast partial dentures from 7 nickel-bearing alloys according to given guidelines. Prior to insertion as well as after 20 min, and in some cases 3 h, resting secretion saliva samples were collected and analyzed for their nickel contents with the aid of atomic absorption spectrometry (AAS) using a graphite tube. Further saliva samples were collected following the insertion of plates inactivated in lactic acid and saline, and after intensive polishing and reinsertion. 20 min after insertion the salivary nickel levels were above the blank value. After 3 h they decreased to the blank value again. The solubility behavior in saliva of the alloys studied was in accordance with the results obtained in corrosion tests in vitro.

Dental Alloys↗
PubMed1989

[Temperature loading of resin-bonded bridges and its effect on the composite strength of the adhesive bond].

Acid-etched prostheses are exposed in the oral cavity to pressure of mastication, to corrosion due to oral fluids, to changes in temperature due to ingestion, and to iatrogenic influences. The changes in temperature which were measured in the adhesive layer were up to +/- 40 degrees C within a range from -2 degrees C up to about 80 degrees C. The bonding agents, which had a high softening temperature and little thermal expansion showed the least influence of temperature after the in-vitro tests. The fact that the tested bonding agents are different in chemistry influenced significantly the adhesive and cohesive characteristics. The thermal tests lead to the conclusion that for clinical use the following adhesives are to be preferred: Bis-GMA modified by monomeric phosphate (e.g. Panavia) and Bis-GMA (e.g. Microfill pontic).

Adhesiveness↗
PubMed1989

[Specific adhesive bonding of air-brushed alloy surfaces].

In vitro test have been conducted to examine if NiCr, CoCr and PdAg alloys air-brushed with aluminium oxide (grain size 250 microns) can be bonded in such a way that the bond resists humidity. After 150 days in water at 37 degrees C the high initial bond strength values of NiCr or CoCr alloys bonded with the modified bis-GMA adhesive Panavia remained unchanged. In the PdAg alloy specimens bonded with Panavia, the initial bond strength were approx. 60% lower than those of the NiCr and CoCr alloys, and were further reduced by approx. 33% after 150 days. As soon as after 15 minutes, the modified bis-GMA adhesive is cured to such an extent that functional loading of the bond interface is possible.

Adhesiveness↗
PubMed1988

The instability of a recombinant plasmid, caused by a prokaryotic-like promoter within the eukaryotic insert, can be alleviated by expression of antisense RNA.

A region of the cauliflower mosaic virus genome was found to direct the expression of a nucleic-acid-binding protein in Escherichia coli. This protein is apparently toxic for the bacteria and leads to a destabilization of plasmids containing that region. Antisense RNA was used to diminish the unwanted expression and to stabilize the respective recombinant plasmids. The approach described may prove useful in other cases where problems with cloning of eukaryotic DNA arise.

DNA Restriction Enzymes↗
PubMed1988

Joining of nonhomologous DNA double strand breaks in vitro.

Extracts of Xenopus laevis eggs can efficiently join ends of duplex DNA that differ in structure and sequence. This was analysed by recircularisation of linear plasmid DNA molecules with dissimilar termini, generated by successive cuts with two different restriction enzymes within the pSP65 polylinker. Use of various enzymes provided blunt ended or 4 nucleotides long 3' and 5' protruding single strand (PSS) termini which were successfully joined in vitro in any tested combination. Sequence analysis of numerous junctions from cloned reaction products of 7 terminus combinations reveal: apart from very rare base exchanges and single nucleotide insertions less than 10% deletions (1 to 18 nucleotides long) were detected. Blunt/PSS or 3'PSS/5'PSS terminus pairs undergo simple "blunt end" joining which preserves PSS ends by fill-in. In contrast, equally polar 3'PSS/3'PSS or 5'PSS/5'PSS terminus pairs are joined by a complex mode: PSS ends overlap by a defined number of nucleotides, set by matching basepairs. Even one basematch suffices to define the setting. This then determines the final mismatch repair and fill-in pattern. We propose that yet unknown terminal DNA-binding proteins stabilize the energetically highly unfavorable configuration of single matching basepairs and help to support defined overlap structures.

Animals↗