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Biomedical subjects

R M Friedman

Publications and source records attributed to R M Friedman.

At least 37 records · Page 2Linked to original sources
PubMed1997

Internal stabilization of autogenous rib cartilage grafts in rhinoplasty: a barrier to cartilage warping.

Autogenous rib cartilage grafts have gained more widespread use in rhinoplasty as dorsal onlay grafts and columellar struts. However, the usefulness of rib as a donor site has been limited by difficulties with postoperative cartilage warping. We hypothesized that the internal stabilization of rib cartilage grafts with Kirschner wires would prevent warping. The costochondral cartilages of a fresh cadaver were harvested and carved into 4 x 10 x 40 nm blocks. A single 0.035-in K-wire was placed longitudinally into the center of each of the study specimens (n = 9), whereas no internal stabilization was utilized in the control group (n = 9). Over a 10-day study period, a mean of 2.2 degrees of warping was observed in the grafts with K-wires as compared to 8.9 degrees in the control group. This indicates that internal stabilization of rib grafts significantly reduces warping (p < 0.001). In a subsequent clinical study, 28 patients underwent placement of internally stabilized columellar struts (n = 19) and/or dorsal nasal grafts (n = 12) using autogenous rib cartilage. At a mean follow-up of 13.5 months (range 3 to 36 months), graft warping was not observed in any patient. Satisfactory aesthetic results were achieved in all but one patient, in whom mild displacement of a dorsal onlay graft occurred. Palatal extrusion of the K-wire occurred in 3 of the first 9 columellar struts. This prompted an alteration in technique with no subsequent extrusions. We conclude that the internal stabilization of autogenous rib cartilage grafts with K-wires effectively prevents graft warpage.

Adult↗
PubMed1996

Effects of a dorsal column lesion on temporal processing within the somatosensory system of primates.

A dorsal column (DC) lesion has lasting effects on behavioral tasks that require temporal processing of tactile information (e.g., frequency and duration discrimination). The present experiments describe physiological correlates of these deficits in temporal discrimination. Compound action potentials evoked by electrocutaneous stimulation were recorded from the major white matter subdivisions of the spinal cord in anesthetized monkeys, and relationships between stimulation frequency and evoked potential (EP) amplitude were determined for the ascending pathways. At 10 pulses per second (Hz) EPs recorded in the lateral spinal columns were attenuated slightly (by 15% or less, relative to 1.5 Hz), whereas potentials recorded from the DCs were not attenuated. The attenuation increased with stimulation frequencies up to 50 Hz, reaching 80% for the anterolateral column and 38% for the dorsolateral column, but only 15% for the DC. Epidural EPs were recorded, before and after interruption of the contralateral DC, from awake animals with electrodes chronically implanted over primary somatosensory cortex (SI). Following the lesion. EP responses to 1.5-Hz stimulation were 46% of preoperative responses to the same stimulus. At 10 Hz, EP amplitudes were attenuated even more, to 27% of the preoperative amplitude at 1.5 Hz. Principal components analysis was employed to quantify alterations in EP conformation and stimulus frequency was varied from 1.5 to 10 Hz, before and after a DC lesion. Interruption of the DC resulted in a significant decrease in the information provided by the EP about changes in stimulus frequency. EPs were also recorded from different locations along the anterior-posterior dimension of the hindlimb region of SI in lightly anesthetized animals. Principal components analysis revealed that there was less information present in the EP about changes in stimulus frequency (1.5-10 Hz) at all recording locations in animals with a DC lesion, compared with the cortex of normal animals. The DC lesion significantly decreased the amplitude of cortical EPs evoked by repetitive stimulation. At 10 Hz the EP was nearly buried in noise, consistent with behavioral deficits in discrimination of the duration of 10 Hz stimulation following interruption of the DC. Also, significantly less information was present in the cortical EPs about changes in stimulus frequency in the absence of intact DCs, which is consistent with deficits in frequency discrimination. This reduction could be explained in part by a lesser capacity of spinal pathways in the lateral column to follow repetitive stimulation above 10 Hz. However, more rostral manifestations of a DC lesion, at either the thalamus or the cortex, are likely to contribute to the reduced capacity of animals with DC lesions to make temporal discriminations.

Action Potentials↗
PubMed1996

Biological effects of the interferons and other cytokines.

There were seven workshops that primarily concerned the biological effects of the interferons and the other cytokines. These were: Workshop 6, The refractory state in the response to interferons (IFNs) and antibodies in treated patients; Workshop 7, IFNs, multiple sclerosis, and the nervous system; Workshop 9, Viral inhibition of the response to IFNs and other cytokines; Workshop 10, Cell growth inhibition by IFNs and other cytokines; Workshop 12, Cytokines and cell death; Workshop 13, Interactions between cytokines; and, Workshop 14, Cytokine gene therapy. Summaries of each of these sessions follow.

Animals↗
PubMed1996

Mechanism of enhancement of the antiviral action of interferon against herpes simplex virus-1 by chloroquine.

Using double immunofluorescence, we have shown previously that interferon (IFN) treatment inhibits the transport of herpes simplex virus-1 (HSV-1) gD from the Golgi complex to the plasma membrane in the virus infected and gD cDNA transfected LMtk-cells. In the present study, we quantitated the gD protein on the cell surface and localized the gD protein in the trans-Golgi network (TGN). The results showed 10-fold less fluorescence for the gD protein on the cell surface in IFN-treated LMtk-cells. Subcellular fractionation studies demonstrated that gD was associated with TGN-enriched membranes. Gold labeling for DAMP distribution using electron microscopy showed that IFN raised the pH of TGN. IFNs induced alkalinization of TGN may be related to the block in the transport of HSV-1 gD. Earlier we reported that a subeffective dose of chloroquine (CHL) or IFN does not change the pHi. However, both CHL and IFN together raise the pHi significantly. To study the biologic significance of the finding, the effect of these subeffective doses of IFN and CHL on the antiviral activity and the transport of the gD protein was studied. Results suggested that CHL enhance the antiviral activity of IFN against HSV-1 and concomitantly increase the inhibition of HSV-1 gD transport. This IFN-induced increase in pHi of the TGN may also explain the inhibitory effect of IFN reported on the terminal steps of some of the enveloped viruses.

Animals↗
PubMed1996

Saline made viscous with polyethylene glycol: a new alternate breast implant filler material.

Silicone shell implants filled with either saline or polyethylene glycol 20,000 at 85 percent weight/volume were placed subcutaneously on the dorsal aspect of 20 rabbits, and after 2 weeks, selected implants were ruptured by subcutaneous insertion of a hypodermic needle. After 6 weeks and 6 months, histologic analyses of tissue samples from both groups showed no deviation in any organ from the norm. Further physical and chemical experiments on these devices showed no contradiction to their use as potential alternative filler material for breast implants in plastic surgery.

Animals↗
PubMed1996

Risk factors for complications in pediatric tissue expansion.

Tissue expansion in children has been associated with complication rates of 20 to 40 percent. A critical analysis of 6 years' (1988-1993) experience with 180 expanders placed in 82 consecutive children was performed to identify those factors which predispose to complications. Major and minor complications each occurred in 9 percent of patients. The factors associated with a statistically significant increase in complications were burns and soft-tissue loss, patient age under 7 years, use of internal expander ports, and a history of two or more prior expansions. In addition, complications were significantly more likely to occur within the first 90 days than during any subsequent expansion. Factors that did not influence complication rate included patient gender, wound drainage upon expander insertion or removal, intraoperative use of antibiotic irrigation, number of expanders placed, use of customized expanders, and operating surgeon.

Adolescent↗
PubMed1996

The role of the testicles in male psychological development.

In this paper the role of the testicles in male psychological development is thoroughly investigated. All previous psychoanalytic studies are reviewed; new clinical material is presented; critical research data from pediatric urology and physiological sex research are utilized. A number of significant conclusions emerge. (1) Certain cases of pathological castration anxiety are explained by a psychosomatic phenomenon (the "testicular vicious cycle") caused by actual and perceived threats to the genitals. (2) Testicular factors may be decisive in various neurotic symptom formations beginning with the early toilet training period. The testicular contribution then takes place along certain preferred pathways of symbolic displacement. (3) Testicular symptoms are observed in many cases of physical and sexual abuse. This finding has application to the treatment of male abuse survivors and to their related sexual dysfunctions. (4) Masturbation involving the testicles is not infrequent in young boys; the most common practice consists of inserting the testes inside the body. (5) The condition of cryptorchism may contribute to psychopathology, especially in the area of masculine self-image; however, cryptorchid boys do not tend to be gender-disordered, effeminate, or prehomosexual. (6) Male body image formation after the phallic stage is a complex emotional and intellectual task involving temporary denial of the inner body and the testicles. Finally it is suggested that a revised account of male sexuality, including both penis and testicles, is a prerequisite for any psychoanalytic theory of gender.

Adult↗
PubMed1995

Comparison of otoplasty techniques in the rabbit model.

The relative merit of cartilage scoring versus suturing in otoplasty remains a subject of debate among leading plastic surgeons. We compared a variety of otoplasty techniques in 42 rabbit ears using anterior or posterior scoring, horizontal or vertical mattress sutures, and combinations of scoring and suturing. The ears were splinted with a right-angle fold for 10 postoperative days, and the animals were killed after 8 weeks. Suturing techniques, alone or in combination with scoring, maintained an angulation significantly closer to the desired 90 degrees than anterior or posterior cartilage scoring (p < 0.05). The greatest accuracy and consistency were seen with horizontal mattress suturing, which provided an average angle (+/- SD) of 86 +/- 8.5 degrees. Histological analysis demonstrated a significant increase in cartilage hyperplasia with suturing alone, whereas the other techniques achieved only mild to moderate increases. Our findings support the usage of horizontal mattress sutures to create the antihelical fold in otoplasty.

Animals↗
PubMed1995

Iloprost enhances survival of axial-pattern skin flaps in an ischemia-reperfusion model.

Iloprost, a stable prostacyclin analogue, significantly enhances the survival of an axial-pattern groin flap in rats after ischemia-reperfusion. Treated flaps showed viability over 90 percent of their area 7 days after an 8-hour ischemic episode, whereas the saline-treated controls were viable over only 20 percent of their area (p = 0.002). This effect was seen at a low (10 ng/kg) dosage, and no apparent side effects were noted.

Animals↗
PubMed1995

Nasal tip blood supply: an anatomic study validating the safety of the transcolumellar incision in rhinoplasty.

The nasal tip blood supply was studied through anatomic dissections and microangiography in 31 fresh cadaver specimens. The lateral nasal artery was present in all specimens, bilaterally in 30 (97 percent) and unilaterally in one (3 percent) and was located in the subdermal plexus 2 to 3 mm superior to the alar groove. The columellar branch of the superior labial artery was visualized bilaterally in 3 specimens (9 percent) and unilaterally in 21 (68 percent), and was absent in 7 (23 percent). Transcolumellar (external rhinoplasty) incisions were performed in 11 of these cadavers prior to dye injection. A consistent crossover flow (100 percent) was seen from the lateral nasal artery arcades to the distal aspect of the transected columellar branches. We conclude that nasal tip blood supply is derived primarily from the lateral nasal arteries, with a variable contribution from the columellar arteries. Collateral flow to the nasal tip may be provided by branches of the ophthalmic artery. The external rhinoplasty transcolumellar incision does not compromise nasal tip blood supply unless extensive tip defatting or extended alar base resections (above the alar groove) are performed.

Angiography↗
PubMed1995

A critical band filter in touch.

Separate mechanoreceptor systems in humans were isolated by varying the spectra of vibrotactile stimuli. First, the function relating threshold to frequency of a sinusoid was obtained on the fingertip for each of four subjects, and it was found to comprise two limbs: a Pacinian and a non-Pacinian limb. The peak sensitivity within the Pacinian limb (mediated by Pacinian corpuscles) was around 250 Hz and spanned the region from 65 to 400 Hz. The non-Pacinian limb showed no detectable change in sensitivity in the region between 10 and 65 Hz. These two limbs were then treated as psychophysical channels in experiments in which narrow band noise and individual sinusoids were used to excite one or both channels. In the second and third experiments, the noise stimuli varied in bandwidth from 8 to 70 Hz and varied in center frequency from 25 to 218 Hz. Masking functions were obtained for ON-frequency conditions (the sinusoidal test and noise masker occupied the same frequency region) and for OFF-frequency conditions (the test and masker occupied different frequency regions). The ON-frequency experiments were used to estimate the signal-to-noise ratio (S/N) of the Pacinian channel at threshold. The OFF-frequency masking experiments were used to infer the shape of the Pacinian channel at frequencies below 65 Hz, where thresholds for Pacinian activation were above detection threshold. The results of these three experiments predicted the findings of a fourth masking experiment with a parameter free model that treated the Pacinian channel as a filter that integrates stimulus power. The results show that the Pacinian channel is analogous to a critical band in the auditory system.

Acoustic Stimulation↗
PubMed1994

Public sector financing of community-based services for children with serious emotional disabilities and their families: results of a national survey.

This article presents the results of a survey of all state directors of mental health programs for children on the agreement with and use of financial policies and practices which promote home- and community-based mental health care for children and adolescents and their families. Whereas only five states reported the implementation of all the financial mechanisms feasible in their states, a majority of states reported the use of mechanisms such as federal funds, state resources and incentives, and flexible funds to encourage the development of community-based care. Results also indicated that states with a local form of government or local district or board that served as the local mental health authority tended to have more of the community-based financial practices in place than did states that contracted directly with providers at the local level.

Adolescent↗
PubMed1994

Fertility after cryptorchidism: a comparative analysis of early orchidopexy with and without concomitant hormonal therapy in the young male rat.

Infertility is common in patients with a history of bilateral cryptorchidism, even after successful prepubertal orchidopexy. Recent data suggest that this defect may be partially due to the existence of hormonal abnormalities in some forms of cryptorchidism. To analyze any potential benefit of hormonal therapy, we have evaluated the immediate and long-term effects of chronic hormonal therapy administered following surgical correction of cryptorchidism. First, using young male rats, we examined the effects of chronic human chorionic gonadotropin (HCG) and a luteinizing hormone-releasing hormone agonist (LHRH-A), alone or combined, on acute pituitary-gonadal axis responsiveness to LHRH administration. High doses of HCG and/or LHRH-A induced deleterious effects on the pituitary-testicular axis in terms of suppression of response to LHRH. Therefore, treatment with a low dose of HCG (50 U/kg/day) for 14 days was used, since it produced a significant increase in intratesticular testosterone (ITT). Second, we tested this hormonal regimen in a cryptorchid rat model. Bilateral cryptorchidism was produced by gubernaculum resection at 14 days of age. Early orchidopexy was performed at age 30 days, and HCG therapy was given from 31 to 44 days of age. Follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone (T) levels were determined before and immediately after hormonal therapy, and at sacrifice. Animals were sacrificed at 61 days of age for determination of serum and testicular hormone levels, accessory sex organ weights and testis histology. Five or six animals from each group were retained for breeding studies at the age of 90 days. Hormonal alterations noted immediately following treatment of cryptorchid animals with HCG are not lasting. The data reveal that the fertility defect in bilateral cryptorchidism is partially prevented by early orchidopexy and that adjunctive hormonal therapy is probably of little additional benefit.

Analysis of Variance↗
PubMed1994

Defective transport of herpes simplex virus glycoprotein in interferon-treated cells: role of intracellular pH.

We have investigated the mechanism(s) of interferon (IFN)-induced inhibition of assembly steps of herpes simplex virus (HSV-1) in mouse LB cells. Data showed that physiological doses of mouse IFN-beta (10-100 IU/ml) significantly inhibited the infectivity (5- to 100-fold) of HSV-1; however, viral protein synthesis was marginally inhibited (2- to 5-fold). Immunofluorescence studies showed that most of the HSV-1gD glycoprotein accumulated intracellularly in IFN-treated LB and LMtk- cells transfected with gD cDNA, as compared to untreated controls, where most of the gD was localized on the plasma membrane. Double-immunofluorescence studies demonstrated that rhodamine-labeled wheat germ agglutinin (WGA) was co-localized with gD protein, suggesting the block was in the transport from the trans-Golgi to the plasma membrane. IFN treatment of LB and LMtk- cells raised the intracellular pH as measured by DAMP distribution and SNARF-1 using laser spectroscopy; this could play an important role in the inhibition of transport of HSV-1gD.

Animals↗
PubMed1993

A novel human cDNA with a predicted protein similar to lysyl oxidase maps to chromosome 15q24-q25.

A novel human cDNA with a predicted protein homologous to the carboxyl end of lysyl oxidase, an extracellular enzyme involved in the maturation of collagen and elastin, has been isolated. The homology to lysyl oxidase begins exactly at the position of the exon 1/exon 2 boundary in the mouse gene (Contente, S., Csiszar, K., Kenyon, K., and Friedman, R. M. (1993) Genomics 16, 395-400). This lysyl oxidase-like gene, which appears to be no larger than 22.1 kilobases, codes for a single polyadenylated RNA species of 2.48 kilobases and has been mapped to chromosome 15q24-q25.

Amino Acid Sequence↗