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Biomedical subjects

M Friedman

Publications and source records attributed to M Friedman.

At least 361 records · Page 20Linked to original sources
PubMed1986

Inactivation of metalloenzymes by food constituents.

Phenylethylaminoalanine (PEAA), derived from biogenic phenylethylamine and dehydroalanine, inhibited the enzymatic activity of the metalloenzyme, carboxypeptidase A (CPA). The inhibition was maximal at pH 7.0 in the pH range 7-8.5. The extent of inhibition increased with time of treatment and PEAA concentration. N-AcetylPEAA did not inhibit the enzyme, suggesting that the free alpha-NH2 group is required for inhibition. PEAA also inactivated the copper enzyme, polyphenol oxidase (tyrosinase). Comparative studies with three other inhibitors, lysinoalanine, ethylenediaminetetraacetic acid and sodium phytate, suggest that the potency of PEAA as an inhibitor of CPA is similar to that of sodium phytate. Of these four inhibitors and three thiol compounds also tested, PEAA was the least and cysteine the most effective against tyrosinase. The pattern of observations in these studies suggests differences in the mechanisms of action of the inhibitors studied. The formation of PEAA, lysinoalanine and sodium phytate in foods is of possible nutritional and toxicological significance.

Carboxypeptidases↗
PubMed1986

Clinical and microbiological effects of sustained release chlorhexidine in periodontal pockets.

Previous studies have shown that a 3-day exposure of the pocket flora to the sustained release of chlorhexidine significantly reduced the relative numbers of spirochetes and motile rods in periodontal pockets to negligible amounts. By 14 days post-treatment, their numbers had returned to pre-treatment levels. The present study extended the exposure time of the pocket flora to the sustained release of chlorhexidine in an attempt to prolong the suppression of the microbial flora for a clinically significant period of time. Clinical parameters were also studied. Sustained release devices (SRD) were inserted into 13 pockets from 8 patients. Pocket depth ranged between 5 and 8 mm. The SRD's were replaced every 3 days to give a total exposure of 9 days. Plaque index (PlI), bleeding on probing and pocket depth were measured, and bacterial samples taken for dark field microscopy and anaerobic culture. There was a marked decrease in the relative proportions of spirochetes and motile rods and the total anaerobic count post-treatment. Pocket depth was reduced in all 13 pockets. These results indicate that a prolonged exposure to chlorhexidine suppresses the pocket flora to negligible amounts and reduces pocket depth for up to 11 weeks post-treatment.

Adult↗
PubMed1986

Percutaneous biliary drainage: complications of 118 consecutive catheterizations.

We have reviewed our experience with 118 biliary catheterization procedures in 109 patients from 1979 to 1984. Major complications (septic shock, hemorrhage, subphrenic abscess, and formation of an arteriovenous fistula) occurred in five patients (4.2%), three of whom died (2.5%). Minor complications occurred in 41 patients. Our success rate using the procedure was 97%. The complications that occurred are described.

Bile Ducts↗
PubMed1986

Deposition, clearance, and effects of aerosolized amiloride in sheep airways.

Persistent Na+ absorption across a relatively Cl- impermeable epithelial barrier may contribute to the smaller water content of airway surface liquid (ASL) in cystic fibrosis. In this study, the feasibility and effectiveness of delivering an inhibitor of Na+ absorption, amiloride, by aerosol to the ASL of awake sheep was evaluated. Aerosolization of 6 X 10(-3) M amiloride, with [14C]amiloride, resulted in an estimated concentration of 7 X 10(-4) M in ASL. The transtracheal electric potential difference (PD), an index of the rate of Na+ absorption, was significantly inhibited (-29%) immediately after aerosolization of amiloride. The inhibition was short-lived and was correlated with rapid disappearance of the drug from ASL (half-time, 10.5 min between 0 and 30 min after aerosolization). Amiloride but not aerosol vehicle increased ASL volume significantly. The unidirectional flow of [14C]amiloride from the lumen to the submucosa across excised, short-circuited sheep airways exceeded flow from submucosa to lumen by a factor of at least 6. This finding suggests that amiloride is actively absorbed and is consistent with the rapid clearance from the airway surface and the short-lived effects of aerosolized amiloride in vivo. We conclude that sufficient concentrations of amiloride can be delivered to sheep airways by aerosol to inhibit PD and Na+ absorption for short periods.

Aerosols↗
PubMed1986

Measurement of cardiopulmonary function in ventilated neonates with respiratory distress syndrome using rebreathing methodology.

The feasibility of using a multiple gas rebreathing technique to evaluate cardiopulmonary function in the ventilated neonate was assessed by measuring functional residual capacity, diffusing capacity of lung for carbon monoxide, and effective pulmonary capillary blood flow in 10 neonates with respiratory distress syndrome. Measurements were first made on the level of positive end expiratory pressure (PEEP) selected by the clinicians caring for the infants ("clinical" PEEP, mean of 4.4 +/- 0.3 cm H2O). To evaluate the effect of PEEP on cardiopulmonary function, PEEP was then changed above (mean of 6.7 +/- 0.4 cm H2O) and below (mean of 1.9 +/- 0.3 cm H2O) this level and measurements were repeated. Mean functional residual capacity on clinical PEEP (10.8 +/- 1.6 ml/kg) was far below the predicted normal and varied directly with changes in PEEP (mean change of 1.2 ml/kg/cm H2O). Diffusing capacity of the lung for carbon monoxide on clinical PEEP was 0.04 +/- 0.01 ml/min/mm Hg/kg and did not change significantly with changes in PEEP. Mean effective pulmonary capillary blood flow was highest (70 ml/min/kg) at the lowest level of PEEP. However, the effect of increasing PEEP on effective pulmonary capillary blood flow in individual infants varied. Increasing PEEP increased arterial oxygen tension but did not cause changes in systemic arterial pressure or heart rate. We conclude that infants with respiratory distress syndrome have severe lung injury with decreased functional residual capacity and diffusing capacity of the lung for carbon monoxide, and that lung volume improves with the use of PEEP.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Monoxide↗
PubMed1986

Nonrecurrent laryngeal nerves and their clinical significance.

The anomalous position of a nonrecurrent laryngeal nerve predisposes the nerve to injury during thyroidectomy and to compression by a thyroid mass. We present three cases in which a seemingly benign thyroid mass traumatized a nonrecurrent laryngeal nerve resulting in either vocal cord paralysis or a vague pressure sensation over the larynx. Some of these patients feel as if they need to clear a foreign body and present with a chronic cough. Normally the nerve is protected from thyroid masses as it passes through the tracheoesophageal groove. In all three patients, surgical excision of the thyroid mass and release of the nerve resulted in recovery of the nerve and resolution of the symptoms. We have found that small, benign, or otherwise asymptomatic lesions of the thyroid gland have a greater tendency to cause vocal cord paralysis in patients with nonrecurrent laryngeal nerves. The surgeon must always be aware of the possibility of the presence of a nonrecurrent laryngeal nerve.

Adenoma↗
PubMed1986

Factors influencing parathyroid allotransplantation in rats.

For nearly a century, researchers have sought to solve the problem of permanent hypocalcemia by allotransplanting the parathyroid glands. A thorough review of the literature revealed conflicting reports, many of which claim success but lack substantial data and sound criteria on which to base the success. At the present, there is no reproducible method of successfully transplanting parathyroid tissue to a nonimmunosuppressed host. The literature on the transplantation of other organs was reviewed in order to determine which methods might be tested on parathyroid tissue to achieve long-term graft survival. These methods include the use of fetal tissue and treatment of the host with cyclosporine. Cyclosporine is unique in that it affects graft rejection but does not alter the nonspecific defenses of the host. Five experimental groups were established to study variables influencing successful allotransplantation. Heterogeneic, parathyroid adult rats with calcium levels below 5.5 mg/dl were the graft recipients. Our criteria for successful parathyroid transplantation included biochemical, functional, and histologic data. Maintenance of serum calcium levels above 8.0 mg/dl was considered biochemical evidence of graft function. Excision of the graft site with the subsequent return to pregraft hypocalcemia was considered evidence of graft function. Histologic evidence of normal parathyroid tissue at the graft site was the final criterion used to prove a successful transplant. Graft failure was documented through serum calcium determinations and histologic examination of the graft site. Rats from group 1 received allotransplanted adult parathyroid glands and showed no evidence of graft function. Animals from group 2 received parathyroid allografts from newborn rats and responded with a transient rise in serum calcium levels. Group 3 rats demonstrated a short period of normocalcemia after receiving fetal parathyroid allografts. In addition to undergoing fetal parathyroid allotransplantation, the rats in group 4 were treated with a 7-day course of cyclosporine. Calcium levels rose quickly and remained elevated for 2 weeks after cessation of cyclosporine. Calcium levels then returned to pregraft levels. Group 5 rats received continuous cyclosporine for 40 to 90 days after receiving fetal parathyroid allografts. These animals showed long-term graft survival by biochemical, functional, and histologic analysis.

Animals↗
PubMed1986

Suppressive effect of delta 9-tetrahydrocannabinol in vitro on phagocytosis by murine macrophages.

Incubation of normal mouse peritoneal cells consisting of over 90% phagocytizing macrophages with delta 9-tetrahydrocannabinol (THC) resulted in a inhibition of phagocytic function. The THC in a dose-related manner suppressed the percentage of macrophages per culture which ingested yeast and the average number of yeast particles ingested by the phagocytizing macrophages. The vehicle used to suspend the THC in vitro, i.e., DMSO, had no detectable effect on macrophage function. Suppression of phagocytosis with no effects on viability or cell number occurred with doses of 10 micrograms or less THC per milliliter culture medium. Measurable suppression also occurred after 24- to 48-hr treatment of the macrophages with the THC. This compound had little if any detectable effect on phagocytosis when added directly to the cultures shortly before testing for phagocytosis. Further studies concerning the effects of THC on macrophage function appear warranted.

Animals↗
PubMed1986

Juvenile nasopharyngeal angiofibroma.

JNA is a highly vascular, benign, yet locally invasive tumor that occurs in preadolescent males. Diagnosis is based on history, physical examination, and radiographic findings. CT scanning is invaluable for evaluating tumor extent. Angiography combined with embolization aids surgeons in identifying the main feeding vessels and decreasing intraoperative blood loss. Surgery is the mainstay of therapy with radiation therapy reserved for inoperable masses. For highly aggressive, recurrent angiofibroma, chemotherapy has shown some promise.

Adolescent↗
PubMed1986

Prostacyclin expression by a continuous human cell line derived from vascular endothelium.

Prostacyclin is primarily an endothelial cell product. It contributes to the important role of endothelium in maintaining the fluidity of blood by inhibiting platelet aggregation and by promoting vasodilation. Endothelial cells in culture tend to senesce, and the level of prostacyclin expression decreases. A permanent human cell line, EA.hy 926, derived from a fusion of primary endothelial cells with cells of a less differentiated line, has been found to sustain basal and stimulated levels of prostacyclin synthesis.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

The effects of ionizing radiation on the pulmonary endothelial cell uptake of alpha-aminoisobutyric acid and synthesis of prostacyclin.

The effects of gamma irradiation (150-3000 rad) on prostacyclin synthesis (PGI2) and Na+-dependent amino acid uptake (alpha-aminoisobutyric acid, AIB) were assessed in vitro in bovine pulmonary artery endothelial cells grown in plastic culture dishes. A dose-dependent increase in both PGI2 synthesis and AIB was found 24 h after irradiation at exposure levels greater than 600 rad. The increase in PGI2 synthesis [297% of sham-irradiated values at 3000 rad, P less than 0.01] was due to an increase in release of arachidonic acid from plasma membrane stores as well as stimulation of cyclooxygenase and/or prostacyclin synthetase enzymes. The increase in AIB uptake (75% increase at 3000 rad compared to sham-exposure values) correlated with the increased synthesis of PGI2 (r = 0.94). There was also a dose-dependent increase in the number of cells that became detached from the culture dishes during the 24-h period after irradiation. The changes in PGI2 synthesis and AIB uptake induced by gamma irradiation differed if the endothelial cells were grown on cover slips, indicating that the endothelial response to irradiation may be dependent on the interaction between the endothelial cell and its extracellular basement membrane matrix.

Aminoisobutyric Acids↗
PubMed1986

Heart rate pattern of a hydrocephalic fetus during cephalocentesis.

Antepartum heart rate recording was performed prior to, during and after cephalocentesis of a hydrocephalic fetus. Signs of fetal distress appeared only after withdrawal of about half of the intraventricular fluid volume, and subside slowly after cessation of the procedure.

Adult↗
PubMed1986

Pregnancy after radiation therapy for carcinoma of the cervix.

A successful pregnancy after intracavitary radiation therapy for carcinoma of the cervix is described. An additional 13 similar cases from the literature are reviewed. The possible reasons for the occurrence of these pregnancies despite irradiation to the ovaries, cervical canal and endometrium are discussed. The fact is emphasized that no genetic damage to the child was expected.

Adenocarcinoma↗
PubMed1986

Thyroid carcinoma.

The mode of presentation, initial findings, treatment, and survival in differentiated thyroid carcinoma were studied in 155 patients. The classic signs, symptoms, and scan findings were present in approximately 70 per cent of the patients, with the remaining 30 per cent displaying unusual manifestations or findings. The effects of neck metastases, extracapsular invasion, and recurrent laryngeal nerve involvement on long-term survival were studied in detail. Prognosis was dependent more on age at initial appearance than any other factor. Patients with prior exposure to radiation had more extensive disease and required more extensive surgery, but they ultimately had the same prognosis for 10-year cure. Treatment of distant metastatic disease by surgery, radioactive iodine, and external radiation resulted in long-term survival in certain cases.

Adolescent↗