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Biomedical subjects

I Zimmerman

Publications and source records attributed to I Zimmerman.

17 recordsLinked to original sources
PubMed1993

Cool, warm, and heat-pain detection thresholds: testing methods and inferences about anatomic distribution of receptors.

We recently found that vibratory detection threshold is greatly influenced by the algorithm of testing. Here, we study the influence of stimulus characteristics and algorithm of testing and estimating threshold on cool (CDT), warm (WDT), and heat-pain (HPDT) detection thresholds. We show that continuously decreasing (for CDT) or increasing (for WDT) thermode temperature to the point at which cooling or warming is perceived and signaled by depressing a response key ("appearance" threshold) overestimates threshold with rapid rates of thermal change. The mean of the appearance and disappearance thresholds also does not perform well for insensitive sites and patients. Pyramidal (or flat-topped pyramidal) stimuli ranging in magnitude, in 25 steps, from near skin temperature to 9 degrees C for 10 seconds (for CDT), from near skin temperature to 45 degrees C for 10 seconds (for WDT), and from near skin temperature to 49 degrees C for 10 seconds (for HPDT) provide ideal stimuli for use in several algorithms of testing and estimating threshold. Near threshold, only the initial direction of thermal change from skin temperature is perceived, and not its return to baseline. Use of steps of stimulus intensity allows the subject or patient to take the needed time to decide whether the stimulus was felt or not (in 4, 2, and 1 stepping algorithms), or whether it occurred in stimulus interval 1 or 2 (in two-alternative forced-choice testing). Thermal thresholds were generally significantly lower with a large (10 cm2) than with a small (2.7 cm2) thermode.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗
PubMed1990

The effect of aging on cardiac autonomic and postganglionic sudomotor function.

Little quantitative information is available on the effects of age on peripheral autonomic function. We studied the effect of age on the heart rate (HR) responses to deep breathing and the Valsalva maneuver in 122 and 155 subjects, respectively, aged 10 to 83 years. The quantitative sudomotor axon reflex test (QSART) was determined in 114 subjects in the same age group. The HR responses were not different between the sexes, but a consistently significant regression with age was demonstrated in response to deep breathing and the Valsalva ratio. The QSART responses were significantly larger in male subjects and were generally lower in older subjects of both sexes but a significant negative regression with age was found only in female subjects. Cardiac vagal function is impaired with age, but postganglionic sympathetic function is little affected by age, suggesting selectivity of effects of aging on autonomic function.

Adolescent↗
PubMed1988

The use of fibrin adhesive in the repair of chondral and osteochondral injuries.

Fibrin adhesive proved to be useful in the reattachment of chondral and osteochondral fragments. Its use is based on sound biological principles. It offers a number of advantages over internal fixation; it causes no further damage to the cartilage, even small chondral fragments can be reattached and a second operation for the removal of metalwork is unnecessary. Its bonding strength provides only contact stability, so that immobilization in plaster for 3 weeks is always necessary. In the last 5 years we have used fibrin adhesive in 28 patients for the fixation of 39 chondral or osteochondral fragments. Of these, 26 cases were followed up for periods of 6 months to 5 years. Twelve patients were examined arthroscopically; 9 of them showed complete healing of the fragments, and only 3 slight localized degenerative changes. In 15 cases we were able to see radiological healing. All except two showed union of the fragments and restoration of the joint surface. In view of our results fibrin adhesive can be recommended for the operative management of cartilage injuries.

Adolescent↗
PubMed1985

Sexual orientation after prenatal exposure to exogenous estrogen.

Thirty women aged 17 to 30 years with documented prenatal exposure to the nonsteroidal synthetic estrogen diethylstilbestrol (DES) were compared to thirty women of similar demographic characteristics from the same medical clinic who had a history of abnormal Pap smear findings. A subsample of the DES women were also compared to their DES-unexposed sisters. Sexual orientation in its multiple components was assessed by systematic semistructured interviews. In comparison to both control groups, the DES women showed increased bisexuality and homosexuality. However, about 75% of the DES women were exclusively or nearly exclusively heterosexual. Nonhormonal and hormonal interpretations of these findings are discussed.

Adolescent↗
PubMed1984

Psychosexual milestones in women prenatally exposed to diethylstilbestrol.

Thirty women aged 17 to 30 years with a record-confirmed history of prenatal exposure to diethylstilbestrol (DES) were compared to 30 women of similar age and demographic background with a history of abnormal Pap smear findings. Heterosocial and heterosexual histories were assessed by systematic semistructured interviews. The groups differed neither in the age at menarche nor in the age at attainment of various psychosexual milestones.

Adolescent↗
PubMed1983

Histamine release into tracheal lumen and bronchial reactivity. Effect of compound 48/80 administered by different routes in various doses on histamine release and bronchial reactivity.

The influence of tracheal lavage with compound 48/80 on the bronchial response to challenge with ACH and AE was studied in 24 animals. Furthermore, the effect of i.v. administration of 48/80 was compared to its administration into the tracheal lumen. No increased histamine liberation was detected in the tracheal fluid after lavage with 48/80, nor was an influence on the bronchial response observed. These observations were the same as those described for tracheal lavage with water. The same amounts of this secretagogue induced, after i.v. administration, a high histamine release which correlates significantly with blood pressure decrease.

Acetylcholine↗
PubMed1983

Histamine release into tracheal lumen and bronchial reactivity. Effect of local histamine administration on histamine release and bronchial reactivity.

The influence of tracheal lavage with histamine, and of i.v. administration of histamine on bronchospastic response was studied in 16 dogs. Airway response to acetylcholine inhalation was significantly increased after tracheal lavage with high concentrated histamine solution (1%). No influence on airway response was found after (1) tracheal lavage with lower concentrations of histamine and (2) its i.v. administration. The clinical importance of these manifestations is discussed.

Acetylcholine↗
PubMed1983

Appearance of [3H]saxitoxin binding sites in developing rat brain.

The binding of [3H]saxitoxin to a crude membrane fraction from rat brains of various ages was determined. We found that at two days before birth, the maximum number of binding sites is 100 fmol/mg of membrane protein. This value increases rapidly for the two weeks following birth, eventually reaching a plateau value of about 800 fmol of toxin sites per mg protein. Since published reports indicate that rat brain myelination occurs primarily between days 15 and 21, we conclude that the development of sodium channels, as measured by [3H]saxitoxin binding, precedes myelination.

Animals↗
PubMed1982

Evolution of an HMO.

Explore the source record for details and available documents.

Blue Cross Blue Shield Insurance Plans↗
PubMed1981

[Proteolytic lung emphysema and obstructive airway disease (author's transl)].

Inhalation of papain by dogs produced morphological changes corresponding to a centrolobular emphysema. The papain inhalation also induced a purulent catarrhal bronchitis. However, the functional changes seen in chronic obstructive bronchitis were not observed. During papain inhalation an increased sensitivity of the bronchial systems develops corresponding to a tremendous increase in bronchospasm in response to Acetylcholine aerosol. The parenchymal lung tissue in dogs is more vulnerable in developing emphysema after papain exposure than is teh bronchial system in developing a chronic obstructive airway disease.

Animals↗
PubMed1980

[Study on the influence of the beta-blocker metoprolol on flow resistance of airways in patients with chronic obstructive disease of airways (author's transl)].

The effect of a single dose of 100 mg metoprolol tartrate (Lopresor) on airway flow resistance, intrathoracic gas volume, systolic and diastolic blood pressure and heart rate was studied in 10 patients with obstructive disease of the airways in a double-blind trial versus placebo. Metoprolol showed no significant effect on the flow resistance in the airways, although in some patients a clear increase in flow resistance was evident. The effect on pulse rate was significant, while that on blood pressure was less pronounced. Therefore the effect of metoprolol on airway flow resistance is similar to that of atenolol and pindolol, while it can be assumed to be superior to propranolol in this respect. The beta 2-stimulator fenoterol is capable of lowering the flow resistance in patients with chronic obstructive disease of the airways extremely satisfactorily, and equally well after metoprolol or after placebo.

Aged↗
PubMed1976

Evaluation of extracorporeal alkylation of red cells as a potential treatment for sickle cell anemia.

Nitrogen mustard and nor-nitrogen mustard inhibit sickling, but the concentrations required would be associated with unacceptable toxicity if these agents were administered to patients. Red cells could be treated extracorporeally and infused back into donors, if the alkylating agent could be removed or inactivated, if the treatment per se did not significantly shorten red cell survival, and if viable alkylated lymphocytes could be eliminated from the treated blood. To estimate whether these conditions could be met in a clinical trial, red cells from four dogs were alkylated at 6-wk intervals. No toxic reactions were observed, although not all nor-nitrogen mustard was removed by the washing procedure. Red cell survival was shortened to about half that of control cells, using concentrations of alkylating agent which reduce sickling by 50%. Lymphocytes from treated blood could still exclude trypan blue, but could not be shown to circulate after reinfusion into donor dogs. If alkylating agents are used to treat patients' cells, inhibition of sickling may outweigh the shortening of red cell life span induced by the treatment; blood should probably be irradiated before infusion to avoid administration of alkylated and potentially mutated, but viable, lymphocytes.

Alkylating Agents↗
PubMed1970

A dipole model for negative steady-state resistance in excitable membranes.

A dipole model is presented for ion flow in excitable membranes. This model considers the membrane to be composed of two distinct regions: a polar region and a nonpolar region. Further, the construction of an electrodiffusive formalism which takes explicit account of the energy of partition required by an ion for passage from external fluid to nonpolar region is presented. In the polar region a cooperative effect is considered which produces a configurational transition of the polar group dependent only on membrane voltage. A resulting change in voltage drop across the polar group is brought about by this configurational transition. This gives rise to a negative steady-state resistance for the equimolar case, in reasonable agreement with observation. The theory, in addition, is in reasonable accord with nonequimolar ion flow, and provides an explanation for such effects as the following: the intercept of the voltage-current characteristic, the ion membrane concentrations inferred from electrodiffusion theories, and the effects of polyvalent cations

Calcium↗
PubMedDate not supplied

Sexual activity level and sexual functioning in women prenatally exposed to diethylstilbestrol.

Thirty women with a history of prenatal exposure to diethylstilbestrol (DES) underwent a detailed sexual history and were compared to a demographically similar sample of 30 women with a history of an abnormal Pap smear. The DES women were found to have less well-established sex-partner relationships and less experience with child-bearing, to be lower in sexual desire and enjoyment, sexual excitability, and orgasmic coital functioning, but to be comparable (and low) with regard to such sexual dysfunctions as vaginismus and dyspareunia. Both potential psychosocial and neuroendocrine explanations are discussed.

Adult↗