Test-retest variability of the auditory brainstem response to bone-conducted clicks in newborn infants

The variability of the auditory brainstem response (ABR) to bone- and air-conducted clicks was investigated utilizing a test-retest paradigm with 20 normal full-term newborn infants. ABRs to bone-conducted clicks at 15 and 30 dB nHL and air-conducted clicks at 30 dB nHL were obtained. The delivery of the bone-conducted signal was controlled. ABR wave V latencies were measured from each test-retest stimulus condition. The results indicated no statistically significant difference in test-retest variability of ABR wave V latencies or amplitudes between bone- and air-conducted clicks. ABRs to bone-conducted clicks, under controlled clinical conditions, are as reproducible and reliable as ABRs to air-conducted clicks in newborn infants.

Effects of alterations in auditory feedback and speech rate on stuttering frequency

This study investigated the effects of altered auditory feedback on stuttering frequency during speech production at two different speech rates, Nine stutterers, who exhibited at least 5% dysfluency during a reading task, served as subjects. They read eight different passages (each 300 syllables in length) while receiving four conditions of auditory feedback: nonaltered, masking, delayed, and frequency altered. For each auditory feedback condition, subjects read at both a normal and a fast rate. Results indicated that stuttering frequency was significantly decreased during conditions of delayed and frequency altered auditory feedback at both speech rates (p < 0.05). These findings refute the notion that a slowed speech rate is necessary for fluency enhancement under conditions of altered auditory feedback. Considering previous research and the results of this study, it is proposed that there may be two interdependent factors that are responsible for fluency enhancement: alteration of auditory feedback and modification of speech production.

Expression of interleukin-1 alpha, interleukin-1 beta, and an interleukin-1 receptor antagonist in human retinal pigment epithelial cells

mRNA expression and protein production of interleukin-1 alpha, interleukin-1 beta and intracellular and secreted forms of an interleukin-1 receptor antagonist were measured in visually confluent monolayers of unstimulated cultured human retinal pigment epithelial cells and after cells were stimulated with recombinant cytokines. Using reverse transcription polymerase chain reaction, transcripts for interleukin-1 alpha and interleukin-1 beta were not detected in unstimulated cells from any of six donors whereas mRNA expression for both interleukin-1 alpha and interleukin-1 beta was readily induced in all six cell lines after cells were stimulated with recombinant IL-1 (alpha or beta), tumor necrosis factor alpha, or lipopolysaccharide. The combination of cycloheximide and recombinant interleukin-1 caused a 14-fold enhancement of interleukin-1 alpha and interleukin-1 beta mRNA expression above that observed after cells were stimulated with interleukin-1 alone. After stimulation by interleukin-1, cells produced intracellular interleukin-1 alpha protein, but did not secrete it into medium. In contrast, interleukin-1 beta protein was not detected in cell lysates or conditioned-medium after stimulation with interleukin-1. An intracellular interleukin-1 receptor antagonist was expressed constitutively by human retinal pigment epithelial cells; mRNA transcripts were enhanced in a dose and time dependent manner after cells were exposed to recombinant interleukin-1 or tumor necrosis factor alpha. In contrast, mRNA for a secreted form of the interleukin-1 receptor antagonist was not detected under basal conditions or after cells were stimulated by recombinant cytokines. Interleukin-1 receptor antagonist protein was found primarily in cell lysates; little interleukin-1 receptor antagonist protein was secreted by the cells. The presence of cell-associated interleukin-1 receptor antagonist was confirmed by immunocytochemistry. Levels of cell-associated IL-1 receptor antagonist protein were not significantly influenced by recombinant interleukin-1 or tumor necrosis factor alpha. Endogenous expression of interleukin-1 receptor antagonist may attenuate the effect of exogenous or endogenous interleukin-1, thus providing the RPE cell a means of maintaining interleukin-1 homeostasis in ocular inflammatory disease.

Modulation of macrophage colony stimulating factor in cultured human retinal pigment epithelial cells

Steady-state mRNA expression and protein production of macrophage colony stimulating factor were measured in visually confluent monolayers of unstimulated cultured human retinal pigment epithelial cells and after cells were stimulated with recombinant cytokines. Using reverse transcription polymerase chain reaction, macrophage colony stimulating factor mRNA expression was detected in unstimulated cells obtained from each of four separate donors. In these cells, mRNA expression was accompanied by secretion of macrophage colony stimulating factor protein into cell-conditioned medium; 48 hr after cells were switched to fresh medium, the mean (+/- S.D.) quantity of macrophage colony stimulating factor, measured by enzyme-linked immunoassay, was 5.1 +/- 2.3 ng 10(-6) cells. There was a dose- and time-dependent induction of macrophage colony stimulating factor mRNA after cells were exposed to recombinant human interleukin-1 and tumor necrosis factor alpha. Maximal mRNA induction was observed in cells exposed for 4 hr to interleukin-1 beta (5 U ml-1) or for 4-8 hr to tumor necrosis factor alpha; under these conditions, macrophage colony stimulating factor mRNA was induced up to 23- and 46-fold after exposure to interleukin-1 beta and tumor necrosis factor alpha, respectively. Similarly, macrophage colony stimulating factor protein production was enhanced after cells were exposed to recombinant cytokines. Protein secretion increased 1.3-2.5-fold (P less than 0.001) after exposure to interleukin-1 beta (5 U ml-1), and 1.2-1.6-fold after exposure to tumor necrosis factor alpha (P less than 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Probe-Tube Microphone Measures of Vent Effects With In-the-Canal Hearing Aid Shells

The acoustic effects of three different configurations of vented in-the-canal (ITC) hearing aid shells were investigated. Real-ear sound pressure level measures (200-2000 Hz) were obtained from unvented and vented ITC shells from 12 adult subjects. In general, with increasing vent size, an increase in the amount of low-frequency reduction and an upward shift in vent kneepoints and vent-associated resonance occurred. The use of venting may be considered clinically for low-frequency reduction in ITC hearing aid frequency responses.

Behavior changes after notification of HIV infection

BACKGROUND

To learn more about how people who did not volunteer for testing react to information about HIV infection, we assessed short-term behavior changes in HIV-positive blood donors.

METHODS

Blood donors who were notified at the New York Blood Center that they were HIV positive were asked to participate in a study. A nurse elicited a medical history, performed a limited medical examination, and asked participants to complete a questionnaire that included questions about drug use, sexual behavior, and psychological characteristics. Participants were asked to return in 2 weeks to complete another questionnaire.

RESULTS

Many fewer men and women reported engaging in unsafe sexual behaviors in the 2 weeks preceding the follow-up visit than had reported such behaviors prior to notification. These changes were greater than those other investigators have reported, but about 40% of the participants still reported unsafe sexual activity at the follow-up interview.

CONCLUSIONS

To make nonvolunteer screening programs for HIV infection more effective in reducing the spread of HIV infection, we need to learn more about how to help people change their high-risk behaviors.

Probe tube microphone measures of loudness discomfort levels in children

Loudness discomfort levels (LDLs) have been advocated as a means for selecting the SSPL90 setting of an individual's hearing aid. Kawell, Kopun, and Stelmachowicz (Ear Hear 1988; 9: 133-136) recently developed a procedure to measure LDLs in children. Several procedural cautions, involving the hearing aid stimulus delivery and sound field calibration, have been noted with this method. As a means of overcoming these problems, a new method utilizing insert earphone derived stimuli delivered to a child's ear-mold with probe tube microphone monitoring of real-ear sound pressure level was explored. Twenty children, aged 7 to 14 years, served as subjects. The advantage of the present method lies in the procedural conveniences and the ability to compare real-ear audiometric measures and hearing aid performance.

Effect of vibrator to head coupling force on the auditory brain stem response to bone conducted clicks in newborn infants

The effect of vibrator to head coupling force on the auditory brain stem response (ABR) to bone conducted clicks in newborn infants was investigated. Twenty full term newborn infants were tested. ABRs to bone conducted clicks were obtained with four different coupling forces (225, 325, 425, and 525 g) at stimulus intensities of 15 and 30 dB nHL. ABRs to air conducted clicks were also obtained at 30 dB nHL. The results of this study indicated that ABR wave V latencies to bone conducted clicks in newborn infants were affected significantly when the vibrator to head coupling force shift exceeded 200 g. It is recommended that the coupling force be controlled and remain consistent when implementing ABR to bone conducted stimuli in newborn infants.

HIV-2 infection in an American

HIV-2 is endemic in West Africa but rare elsewhere. In the USA there have been 18 reported cases of HIV-2 infection; most identified people have been West Africans. We recently diagnosed the first case of HIV-2 infection in a native-born US citizen, a woman whose serum was found to be reactive to anti-HIV-1 enzyme immunoassay (EIA) when she attempted to donate blood in 1986. Although both HIV-1- and HIV-2-specific EIAs were reactive, the anti-HIV-2 Western blot (WB) was positive, while the anti-HIV-1 WB was positive or indeterminate on different occasions. Synthetic peptide testing was reactive for HIV-2 but not HIV-1. HIV-2 DNA was detected using the polymerase chain reaction procedure. Although she had travelled to West Africa, it is unclear how she became infected with HIV-2.

Test-retest variability in audiometric threshold with supraaural and insert earphones among children and adults

The effect of age and earphone condition on test-retest intrasubject variability in audiometric threshold was investigated. Ten subjects in each of the following age groups were investigated: 6-9 years, 10-13 years and young adults. Test-retest audiometric thresholds were collected at six frequencies (250, 500, 1,000, 2,000, 4,000 and 8,000 Hz) under three earphone conditions (Telephonics TDH-50P supraaural and Etymotic Research ER-3A insert earphone coupled to an immittance probe cuff or a foam insert). No statistically significant differences were found in variability of test-retest differences as a function of age, earphone condition or test frequency (p greater than 0.05). The clinical application of the insert earphone is recommended with children and adults as it affords no greater test-retest variability and at the same time provides a solution to a number of limitations incurred with the use of the supraaural earphone.

Effect of temporal area bone vibrator placement on auditory brain stem response in newborn infants

The effect of bone conduction vibratory placement on the temporal area, revealed by the auditory brain stem response (ABR), in newborn infants, was investigated. Twenty-five full term neonates were tested at 48 to 72 hours postparturition. ABR wave V latencies were obtained from three different temporal area postauricular vibrator placements at 15 and 30 dB nHL stimulus intensity levels. Results showed that significant ABR wave V latency shifts were observed with changes in the three vibrator placements (p less than 0.05). It is suggested that, with ABR testing in newborn infants using bone conducted stimuli, bone vibrator placement on the temporal area remain consistent.

Computer assisted treatment planning for 125I ophthalmic plaque radiotherapy

This paper describes a computer program for planning the treatment of ocular tumors with 125I plaques. The program permits the input of the tumor configuration into a model eye and facilitates the viewing of the relative geometry of the tumor and various eye structures in different perspectives. Custom-designed 125I plaques can be localized onto the globe, and dose distributions can be calculated and superimposed on the eye structures in any plane or on the inner eye surface. The program allows efficient evaluation of the plaque design in terms of radiation dose distribution relative to the tumor and critical structures.

High-dose combination cyclophosphamide, cisplatin, and melphalan with autologous bone marrow support. A clinical and pharmacologic study

A total of 23 patients were treated at five dose escalations with high-dose combination cyclophosphamide, cisplatin, and melphalan with autologous bone marrow support. The maximum tolerated doses of cyclophosphamide, cisplatin, and melphalan were 5,625, 180, and 80 mg/m2, respectively. The dose-limiting toxicity was cardiac toxicity. Objective tumor regression occurred in 14 of 18 evaluable cases, with a median duration of 3.5 months. Pharmacokinetic evaluation of melphalan in 20 patients revealed a dose-related increase in maximum plasma concentration (Cmax) and area under the curve (AUC). Perturbation of the melphalan plasma half-life and AUC, associated with severe toxicity, resulted when renal insufficiency occurred. The results suggest that high-dose combination cyclophosphamide, cisplatin, and melphalan produces frequent, rapid responses in breast cancer, melanoma, and sarcoma, although with significant extramedullary toxicity. The pharmacokinetics suggest that modification of the treatment schedule may result in a reduction of treatment-related toxicity.

Neutrophil migration is defective during recombinant human granulocyte-macrophage colony-stimulating factor infusion after autologous bone marrow transplantation in humans

We have previously reported that continuous intravenous (IV) administration of recombinant granulocyte-macrophage colony-stimulating factor (rHuGM-CSF) to humans following high-dose alkylating agent chemotherapy and autologous bone marrow support (ABMS) results in myeloid bone marrow maturation, accelerated granulocyte recovery, and reduced treatment-related toxicity. However, we found that leukocyte counts declined rapidly after discontinuation of rHuGM-CSF therapy, which suggests possible growth factor effects on leukocyte margination and migration. For these reasons we studied granulocyte margination by using 111In-labeled autologous granulocytes and found similar granulocyte margination before (21.5% +/- 13.4%) and during continuous IV rHuGM-CSF infusion (23.3% +/- 9.6%). Phagocytosis of Cryptococcus neoformans and granulocyte hydrogen peroxide production was similar before and during rHuGM-CSF infusion and similar to patients treated with the same high-dose chemotherapy and ABMS but not receiving growth factor. However, migration of granulocytes to a sterile inflammatory site was markedly reduced during continuous rHuGM-CSF infusion (1.2 +/- 0.9 WBCs/cm2, 24 hr) as compared with baseline (39.6 +/- 17.7 WBCs/cm2/24 hr; P less than .0008). These findings may be of relevance when extravascular granulocytes are required for host defense.

Clinical and pharmacologic effects of high dose single agent busulfan with autologous bone marrow support in the treatment of solid tumors

A Phase I-II clinical trial of high dose single agent busulfan (16-20 mg/kg) administered over a 4-day period was undertaken. Pharmacokinetic measurements reveal that steady state total plasma busulfan levels between 2 and 10 microM were achieved by the second day and maintained through the remaining treatment period. Urinary excretion of mutagenic activity monitored by the Salmonella mutagenesis assay persisted for up to 48 h following the last dose of busulfan. The treatment showed specificity for myelocytic precursors as evidenced by selective depression of granulocytes with relative sparing of lymphocytic elements, and by differences in DNA damage as measured by a nucleoid sedimentation assay. Dose limiting toxicity was mucositis, anorexia, and hepatic toxicity. Transient autoimmune disorders were observed in three of the six patients. Partial responses were seen in two of five patients with melanoma, but these lasted for only 2 and 3 months. High dose busulfan represents an alkylating agent with marked myelocytic selectivity and may be useful for inclusion in intensive combination regimens.

Restoration of functional continuity in dystrophic murine muscle after crushing

The recovery of functional continuity after crush injury was measured by a simple electrophsiological technique in semitendinosus muscles of normal and dystrophic mice of the C57BL/6J(dy2Jdy2J) strain. In contrast to virtually complete restitution in normal muscles, only one-third of fibers regained continuity in dystrophic muscles. The study also confirmed the lower resting membrane potentials of dystrophic fibers and the presence of "functional" denervation in some of them.

Absence of fibrillation after muscle injury

The possibility was examined that fibrillation potentials may occur in those parts of muscle fibers which become functionally denervated following segmental necrosis. Focal necrotic lesions were induced in rat semitendinosus muscles by crushing, ligating, or cutting muscle fibers. When the treated muscles were examined microscopically and recordings made with intracellular or extracellular electrodes, fibrillations were found to be either completely absent or extremely infrequent. Fibrillation potentials were also absent in the brachioradialis muscle of a human subject after myotomy. In contrast to these negative results, surgical denervation of the rat semitendinosus induced fibrillation activity within 3 days; when fully developed, fibrillations occurred in approximately one-half of the fibers at any time. The findings are considered to have significance for an understanding of the pathogenesis of those "myopathic" disorders in which fibrillations are found.

Zinc supplementation and its effect on taste acuity in children with chronic renal failure

Diminished taste acuity (hypogeusia) and zinc deficiency have been reported in children on maintenance haemodialysis and with varying degrees of chronic renal failure. We have studied the effect of 6 weeks' zinc supplementation in 20 children with chronic renal impairment using a double-blind crossover trial. Although we achieved significant increases in serum zinc levels no significant improvement in taste acuity could be demonstrated. These studies provide no support for the belief that routine zine supplements are necessary in children with chronic renal failure.

2,4-diamino-5-benzylpyrimidines and analogues as antibacterial agents. 6. A one-step synthesis of new trimethoprim derivatives and activity analysis by molecular modeling

A new route to 2,4-diamino-5-(4-hydroxybenzyl)pyrimidines has been developed that involves the condensation of 2,4-diamino-5-(hydroxymethyl)pyrimidine with phenols in acidic medium. The use of phenol and its 2,6-dialkyl derivatives produces 5-(4-hydroxybenzyl)pyrimidines exclusively. However, 2,6-dimethoxyphenol produces a mixture of 5-(3-hydroxy-2,4-dimethoxybenzyl)- and 5-(4-hydroxy-3,5-dimethoxybenzyl)pyrimidines. The phenolic condensation has been used to prepare a series of alkyl-substituted 5-(4-hydroxybenzyl)- and 5-(4-alkoxybenzyl)pyrimidines. The use of 1,2,3-trimethoxybenzene in place of a phenol produces 2,4-diamino-5-(2,3,4-trimethoxybenzyl)pyrimidine, a trimethoprim isomer with low antibacterial activity. The use of molecular models of several of the new ortho-substituted derivatives in the active site of dihydrofolate reductase has provided a rational explanation for their activities relative to trimethoprim.

A new method of dosimetry-a study of comparative laser-induced tissue damage

The use of lasers in medicine and surgery has increased slowly-its effectiveness based on trial-and-error clinical experience. Very little comprehensive data has been published that scientifically presents dosage, energy, absorption, and comparisons between types of lasers. Our laboratory has developed a method for taking the guesswork out of laser dosage using scientific data to optimize therapy and give reproducible responses. Experiments were conducted using an argon laser, a neodymium: YAG laser, and a broad-band infrared light source. This preliminary study uses a beam scan technique, which for the first time permits accurate measurement of the laser intensity incident on tissue. Therefore, this protocol allows the standardization of dosage measurements with good experimental reproducibility in biological models. By using this accurate method of measuring the intensity delivered to pigskin, we are able to reproduce for the first time similar histological damage with the different energy sources.

The Absolute Configuration of a Sesquiterpene Enone From Stevia purpurea and a Phenol From Lasianthaea podocephala

(6S,1'R)-6-(1',5'-Dimethylhex-4'-enyl)-3-methylcyclohex-2-enone (1a) has been prepared and found to be the enantiomer of an enone obtained from Stevia purpurea. Oxidation of enone (1a) gives (R)-2-(1',5'-dimethylhex-4'-enyl)-5-methylphenol, identical with a natural product from Lasianthaea podocephala.