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Biomedical subjects

M Loeb

Publications and source records attributed to M Loeb.

At least 19 recordsLinked to original sources
PubMed1992

Hemolymph concentrations of host ecdysteroids are strongly suppressed in precocious prepupae of Trichoplusia ni parasitized and pseudoparasitized by Chelonus near curvimaculatus.

Regulation of ecdysteroid production in lepidopteran prepupae was studied using a parasitic wasp (C. near curvimaculatus) which specifically suppresses host prepupal ecdysteroid production after the induction of precocious host metamorphosis. At the developmental stage at which the hemolymph of the unparasitized metamorphosing host has its maximum titer of prepupal ecdysteroids, the hemolymph of 4th instar "truly parasitized" hosts (hosts with a surviving endoparasite) had a strongly reduced ecdysteroid titer. However, during the photophase about 12 h later, just prior to emergence of the parasite larva, an ecdysteroid peak was observed in the host hemolymph. Fourth instar pseudoparasitized prepupal hosts (in which the endoparasite was not present or died early in development) exhibited a sustained suppression in the hemolymph ecdysteroid titer. Small 5th instar pseudoparasitized hosts, which normally would molt to a 6th instar prior to metamorphosis, but which precociously attained the prepupal stage, also had a strongly reduced ecdysteroid titer. The late increase observed in truly parasitized hosts could be completely prevented by surgical removal of the parasite 24 h earlier, resulting in a titer similar to that in pseudoparasitized hosts. HPLC analysis of ecdysteroids in normal, truly parasitized, and 4th or 5th instar pseudoparasitized prepupae showed that both ecdysone and 20-OH ecdysone* were suppressed in truly and pseudoparasitized prepupae, with ecdysteroid levels being lowest in pseudoparasitized hosts. These data, and those of Brown and Reed-Larsen (Biol Contr 1, 136 [1992]), showing endoparasite secretion of ecdysteroids just prior to its emergence from the host, strongly indicate that: (1) the prepupal peak in truly parasitized hosts originates from the endoparasite, and (2) the low level of ecdysteroids in pseudoparasitized hosts results from the host's intrinsic inability to express a normal level of prepupal ecdysteroid titer. While precocious 4th or 5th instar prepupae of similar size had similarly suppressed ecdysteroid titers, smaller 4th instar prepupae had a lower ecdysteroid titer than larger, precocious 5th instar prepupae. Rare 5th instar pseudoparasitized prepupae that were of nearly normal size showed a prepupal ecdysteroid titer distinctly greater than those of the usual smaller, precocious 5th instar prepupae. The data suggest that the competence of the host to express a normal hemolymph titer of prepupal ecdysteroids is more closely correlated with the size of the prepupae than with the instar attained.

Animals↗
PubMed1992

Fibrinolytic activity as a predictor of the outcome of prolapsed intervertebral lumbar disc surgery with reference to background variables: results of a prospective cohort study.

In a prospective study 122 patients with a slipped lumbar disc and no previous surgery were preoperatively examined for fibrinolytic activity. Surgical results for these patients were evaluated 12 months postoperatively by clinical overall assessment. In a multiple linear regression analysis fibrinolytic variables, euglobulin clot lysis time and plasminogen activator inhibitor 1, were shown to have predictive value regarding outcome of surgery; that is, normal fibrinolytic activity favors a satisfactory outcome and vice versa. Background variables and lipid profile were also recorded preoperatively. Body mass index, gamma-glutamyl transpeptidase, triglycerides and smoking were of statistical significance in relation to euglobulin clot lysis time and plasminogen activator inhibitor 1. Postoperative fibrinolytic re-examination of 20 patients seem to confirm that patients at risk of surgical failure have a prolonged depression of fibrinolytic activity.

Cohort Studies↗
PubMed1986

Postoperative radiotherapy in breast cancer--long-term results from the Oslo study.

The long-term results of a randomized clinical trial evaluating the effect of postoperative radiotherapy as an adjuvant to radical mastectomy are presented. There were 1115 patients including 27 protocol deviants. The follow-up time is 11-20 years. In the first part a conventional roentgen unit was used, and in the second part a 60Co unit, with considerably increased dosage and altered treatment plan. Both types of radiation techniques lowered the incidence of loco-regional recurrences significantly, but had no significant influence on the overall survival. The relapse-free survival was significantly improved by 60Co radiation in Stage II patients, but was unaffected by radiation in the other subgroups. Regarding survival, Stage II patients with medially located tumors seemed to benefit more from 60Co radiation than those with lateral tumors. A significant increase in the number of deaths caused by myocardial infarction was observed in Stage I patients having 60Co radiation, indicating that the radiation dose to the heart is of significance.

Aged↗
PubMed1985

Doxifluridine (5'-dFUrd) in patients with advanced colorectal carcinoma. A phase II study.

Infusion of 5'-dFUrd (2.0-3.0 g/m2 over 1 h on days 1-5 every 3rd week) resulted in one partial response in 21 patients with advanced and progressing colorectal cancer. No patient had received chemotherapy before the 5'-dFUrd trial. Hematological and gastrointestinal toxicity were generally mild. In 4 patients peripheral neurotoxicity was diagnosed during treatment, whereas transient cerebellopathy was observed in one. Cardiac side effects (repeated angina pectoris following 5'-dFUrd infusion) led to discontinuation of treatment after two courses in one patient. It is concluded that 5'-dFUrd at the above doses is not superior to conventional 5-FU treatment in colorectal cancer. Neurological and cardiac side effects are rare but may be a problem in individual patients.

Angina Pectoris↗
PubMed1985

Post-treatment fertility in patients with testicular cancer. I. Influence of retroperitoneal lymph node dissection on ejaculatory potency.

"Dry ejaculation" occurred in none of 15 patients with testicular cancer treated by right-sided retroperitoneal lymph node dissection (RLND). After left-sided and bilateral RLND, "dry ejaculation" was observed in 7/21 and 51/61 men respectively. Twelve of 21 patients with "dry ejaculation" or small volumes of seminal fluid had true retrograde ejaculation. In 7 of 10 men the ejaculatory volume increased significantly after treatment with imipramine chloride. Four men impregnated their wives during treatment with the drug. Without impairing the results of therapy it is possible to spare fibres from the sympathetic chains and pre-sacral plexus during RLND due to testicular cancer, thus preserving fertility in at least 40% of patients.

Adolescent↗
PubMed1985

Post-treatment fertility in patients with testicular cancer. II. Influence of cis-platin-based combination chemotherapy and of retroperitoneal surgery on hormone and sperm cell production.

Active sperm production was observed in 20 of 35 patients with testicular cancer 1 year after discontinuation of all treatment (retroperitoneal surgery only: 13; cis-platin-based chemotherapy (CVB) +/- other treatment: 22). The percentage of patients who regained spermatogenesis increased slightly after a further 1 to 2 years. Fourteen patients (of 121 under observation) impregnated their wives (after retroperitoneal surgery: 9; after CVB +/- other therapy: 5). The individual serum FSH values correlated significantly with the results of sperm analysis: an FSH value greater than or equal to 20 iu/l indicated azoospermia in 8 of 12 patients, whereas only 5 of 30 patients with FSH levels less than or equal to 12 iu/l were azoospermic. Serum testosterone and pituitary serum LH were virtually unaffected by the treatment. In conclusion, 1 to 3 years after cis-platin-based multi-modality treatment for testicular cancer, 50 to 60% of patients have active spermatogenesis and fatherhood can be achieved by a significant number of them.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

Prediction of tumour progression in superficial bladder carcinoma.

In a retrospective study, prognostic factors have been analyzed in 45 patients with superficial bladder carcinoma (Tis, Ta, T1) with subsequent progression to invasive (T2, T3, T4) and/or metastatic (M+) disease. The findings are compared with those from a control group of 17 patients with no subsequent invasive or metastatic disease. In a single-parameter analysis the following parameters were significantly associated with a high risk of developing invasive disease: tumour multiplicity; tumour invasion of blood and/or lymph vessels; increasing histological grade, and the history of previous surgical treatment. In a multivariate analysis, multifocality, small vessel infiltration and previous treatment per time (TPT factor) were significantly related to the risk of subsequent progression. An arbitrary score system revealed that progression could be predicted significantly in patients with a high score.

Aged↗
PubMed1984

Isolation of crustacean erythrophore concentrating hormone from nerve tissue of Homarus americanus.

Crustacean erythrophore concentrating hormone (CECH) was isolated from lobster (Homarus americanus) eyestalks by reverse phase high-performance liquid chromatography (rp-hplc). Putative lobster CECH fractions co-chromatographed with commercially available pure CECH on two independent rp-hplc systems, and were positive for activity by bioassay. CECH was detected in eyestalk, but not brain homogenates.

Animals↗
PubMed1983

Improvement in survival after recurrence of carcinoma of the breast.

The survival experience of 187 patients who developed recurrent breast carcinoma during the years 1961-1968 was compared to a similar series of 70 cases whose recurrences developed between 1975 and 1978. 'Modern' combination chemotherapy was available for the treatment of the later series of patients only. Survival from the time of recurrence was significantly longer in the more recently treated patients (median 22.8 vs 13.3 months, P = 0.002). The difference persisted when factors known to influence survival after recurrence were taken into account and did not appear to be due to earlier diagnosis of recurrence. These results, which suggest an impact of chemotherapy upon survival, are consistent with a few other studies, but contrast with recent reports from randomized trials that combination chemotherapy fails to prolong life. Possible explanations for these discordant findings are suggested.

Breast Neoplasms↗
PubMed1982

Do pili play a role in pathogenicity of Haemophilus influenzae type B?

Surface components of Haemophilus influenzae type b (Hib) responsible for mucosal adherence were identified through assay of in-vitro attachment to human buccal epithelial cells (EC). Among many Hib strains from cerebrospinal fluid, blood, or the nasopharynx (NP), two isolates from NP were found to be exceptionally adherent. Adherence correlated with agglutination of human red blood cells (RBC). The adherent strains displayed pili, not previously described for Hib or other encapsulated H. influenzae. Moreover, highly adherent, piliated subpopulations of bacteria could be selected from any strain, but were lost upon subculture. Thus, the potential to express pili may be general for Hib and may aid the NP colonisation which precedes systemic invasion by this organism. Piliation was correlated with the amount of an outer membrane protein with a molecular weight of about 20,000 daltons, which had proved to be immunogenic in an 8-month-old child.

Adhesiveness↗
PubMed1981

The present state of research on the effects of noise: are we asking the right questions?

A review is presented, with a bibliography of 68 items, of some effects and aftereffects of noise on other senses and on intelligence, on performance on multiple tasks, memory, computation, vigilance, signal detection, reaction time, and on industrial performance. Throughout this literature contradictions abound. Mechanisms reviewed include distraction, arousal, stress, concentration, masking of task-produced feedback, erasure of auditory store, and interference with or inhibition of articulation and rehearsal. It was concluded that it is necessary to consider complex interactions of the effects of noise with task difficulty and task proficiency of the subject, personality of the subject, time of day, food and drug ingestion, and the meaning of the noise and the previous exposure of the subject to it, whether it represents a threat or interference with work or reaction, or is in fact interesting and enjoyable. Such information must be available before generalizing.

Arousal↗