An independent evaluation of second generation suction microkeratomes.

Microkeratome designs for lamellar refractive surgery have changed significantly in recent years. Three microkeratome systems (Automatic Corneal Shaper (Steinway Instrument Company, Inc, San Diego, Calif), Draeger Lamellar Keratome (Storz Instrument GmbH, Heidelberg, Germany), and Microprecision test model (Microprecision Instrument Company, Inc, Phoenix, Ariz) were subjected to a concurrent and independent evaluation. Three types of keratectomies (primary superficial stromal, secondary intrastromal, and primary deep stromal) were performed under identical conditions in human cadaver eyes. The resected discs and the beds were observed for uniformity, accuracy, centering, and smoothness. Scanning electron microscopy of the corneal beds and cutting blades was done. The three systems produced irregular surfaces with chatter lines that appeared least rough with the Draeger rotating machine. The average primary and secondary section diameters were undersized by 10% in all three systems. The average primary keratectomy thickness was more accurate with Steinway, but the variability was over 20 microns in all three systems. Regarding the average secondary keratectomy thickness, Steinway tended to cut thicker, whereas Draeger and Microprecision tended to cut thinner than attempted. The Draeger blade presented the smoothest edge. All three systems need substantial improvements to produce more accurate, reproducible, and smooth resections. More reliable methods to accurately measure the thickness of the resected cornea should be developed.


Predicting visual performance following excimer photorefractive keratectomy.

A duplex optical image is created when the ablation zone formed by excimer photorefractive keratectomy is smaller than the entrance pupil. Visual performance and secondary effects are analyzed using a theoretical model of the optical image. A point-spread function having a centered in-focus component surrounded by an annular out-of-focus component is calculated from pupil size, ablation size, refractive error, and photoreceptor directional sensitivity. The line-spread, edge-spread, and optical transfer functions are derived. In the line- and edge-spread functions, secondary maxima and curvilinear ramps are most evident with low refractive errors. The half-height widths of the point- and line-spread functions change little. The optical transfer function is reduced in proportion to the distribution of light between the image components. Stable point and line half-height widths explain why Snellen visual acuity is insensitive to annular blur. Contrast sensitivity correlates with symptoms of haze and fog. Halos and ghost images are associated with secondary optical maxima and curvilinear ramps. Neither visual acuity nor contrast sensitivity can predict halos or ghost images. Halos and ghost images will be most prevalent in low illumination and for low refractive corrections. High refractive errors will produce fewer visual side effects than low refractive errors.


Silicon cast method for quantification of photoablation.

Topometry and measurement of photoablation patterns are key questions for keratorefractive photoablation. Ablation rates have been determined previously by either tissue perforation or by micrometry performed on histologic sections. A three-dimensional cast of cornea after irradiation was made by using a two-component silicon gel that polymerizes within minutes, thus preserving the corneal topography immediately after photoablation. Polymerization is athermal and nontoxic. The resulting silicon blocks were cut perpendicularly to the anterior surface and measured by calibrated light microscopy. The silicon surface is extremely smooth and the accuracy of the cast is better than 0.25 micron. Reproducibility and long-term stability were demonstrated for casts of photoablated polymethylmethacrylate. Thus, ablation rates and profile, volumetry, and topometry can be determined following laser ablation. The method has been applied for 193-nanometer excimer laser in vitro irradiation of the human cornea. Ablation rates in Bowman's layer and stroma for various radiant energies and distinct pulse numbers were found to be in agreement with published data, and an incubation effect for the first laser pulses could be demonstrated. The method is nondestructive, accurate, inexpensive, practical, and reduces requirements for laboratory animals.


A comparison of excimer laser (308 nm) ablation of the human lens nucleus in air and saline with a fiber optic delivery system.

Photoablation with excimer lasers has demonstrated precise tissue cutting and minimal thermal damage. Potential ophthalmic applications of these lasers include remodelling of the corneal surface, glaucoma treatment, and phacoablation. Ablation of human lens with a 308 nm XeCl excimer laser light delivered through a fiber has been demonstrated in preliminary experiments. Intraocular delivery of laser light must be done in a fluid medium to preserve the integrity of ocular structures. However, little information is available on the effect of the fluid media on the ablation process. Therefore, a series of experiments was conducted to determine whether the ablation of human lens nucleus at 308 nm via a fiber differs in air and saline media. Ablation of human lens nuclei (n = 30) was conducted with a XeCI excimer laser (308 nm) coupled to a 600 microns core size fiber. Irradiation was performed at 2.8 mJ/cm2 energy density and 20 Hz. The fiberoptic was brought to contact with the lens nucleus and remained fixed for the duration of irradiation. Variables consisted of the medium (air or saline) and number of pulses delivered (100 to 10,000). Following establishment of the tissue shrinkage ratio, the depth of each crater and the tissue volume removed were measured histologically. The histological features of nucleus ablation in air and in saline were also examined with both light and scanning electron microscopy. Light microscopy revealed that the average zone of thermal damage adjacent to the crater is thinner in the presence of saline (60 microns, SD = 6 microns) than it is in air (90 microns, SD = 12 microns). In both media, the thickness of the zone of thermal damage is greater at the surface than it is at its base. Following irradiation in air, deep sharpedged craters with smooth walls are formed. Craters formed by irradiation in saline are characterized by reduced depth and irregular walls. For the same number of pulses applied (500, 1000, and 2000), the mean depth of ablation per pulse in air (8.6 to 2.7 microns/pulse) was greater by approximately a factor of two than that in saline (4.10 to 1.30 microns/pulse) at P < .01. However, the mean ablated volume removed per pulse was greater in saline (0.00250 to 0.00150 mm3/pulse) than in air (0.00120 to 0.00080 mm3/pulse), for the same number of pulses (1000, 2000) at P < .01. In comparing the data for the same number of pulses applied in air and in saline, it appears that the depth of crater formed by irradiation in air is deeper than that in fluid. The overall volume ablated is greater in fluid than it is in air at 1000 and 2000 pulses. Additionally, the zone of thermal damage is thinner in the presence of saline than it is in air. Smoother crater shapes were observed following irradiation in air than in saline. These results suggest that under this specific experimental setup, the ablation in saline is different from that in air.


Modified surgical technique for repeated epikeratophakia surgery in aphakic eyes.

Incomplete epithelial removal from the peripheral keratectomy at the time of repeat epikeratophakia surgery can lead to interface downgrowth and consequent failure, as observed in the case reported herein. We present a modification of the standard surgical technique aimed at avoiding such complication. A 69-year-old white female underwent a third aphakic epikeratophakia modified to reduce the risk of epithelial interface downgrowth, which had caused a previous failure. The aphakic tissue lens, 8.5 mm in diameter, was sutured into a corneal pocket obtained at a deeper level, inside the peripheral keratectomy used for the previous two procedures. Useful visual acuity (20/60) was obtained and the refractive outcome remained stable up to 1 year postoperatively. Epithelial interface downgrowth did not recur. Despite the possible risk of perforation while undermining the recipient cornea at a deeper level, the modified technique might offer a more effective method of preventing epithelial downgrowth after repeat epikeratophakia surgery.


Corneal wound healing after excimer laser ablation in rabbits: expanding versus contracting apertures.

Photorefractive keratectomy for myopia can be performed using an expanding or contracting iris diaphragm, either of which allows for greater ablation centrally and less tissue ablation toward the edge of the treatment zone. To compare the effects of these two strategies, eight rabbits underwent bilateral 5.00-diopter myopic ablations, performed with a contracting diaphragm in one eye and an expanding diaphragm in the other. The rate of epithelial healing and degree of anterior stromal haze, monitored by a masked observer, were similar for the two groups, as was the amount of corneal flattening. These results in rabbit corneas do not suggest a particular advantage of either the expanding or contracting apertures for achieving central corneal flattening in photorefractive keratectomy.


Surgical correction of hyperopia: a new experimental approach using X-incision and suture technique in rabbits.

A new experimental surgical technique to correct hyperopia by steepening the central corneal curvature was performed on the eyes of rabbits. After X-shaped incisions at four quadrants of the paracentral cornea, four deep, transverse interrupted sutures were placed across the incisions and the knots were tightened to compress the corneal tissue in the direction of the suture. Twenty-three eyes of 12 albino rabbits were divided into group A (7 eyes) with a 4-millimeter diameter clear zone, group B (9 eyes) with a 6-millimeter diameter clear zone, and control group C, consisting of 7 contralateral eyes of group A without any incision or suture. There was significant (p < .01) steepening of the central cornea as measured by the keratometer at postoperative 8 weeks in group A (+1.88 diopters) and group B (+1.68 D) compared with that of the control group C (-3.44 D). The difference in effect of hyperopic correction between groups of A and B was not statistically significant. This procedure serves only as an experimental model of corneal response to incisions and sutures and is not for use in human corneas.


Facilitation of ab interno radial keratotomy by air keratoplasty.

Ab interno radial keratotomy is a keratorefractive procedure with radial incisions made by externalizing a blade inserted in the deep stroma. A major limitation of the procedure is the technical inability to establish a safe pre-Descemetic stromal entry of the blade with subsequent suboptimal depth of the radial incisions. A technique to delineate Descemet's membrane was investigated to obtain deeper incisions with the ab interno radial keratotomy. Air was injected with a 30-gauge needle mounted on a 3-milliliter syringe and entering the deep stroma at the limbus in human donor eyes. The injection was done in a pulse fashion with the needle tip advanced 3 mm away from the limbus. Ab interno radial keratotomy was then performed with and without air injection. Bubbles were localized to the pre-Descemet region. The depth of the radial keratotomy incisions increased from 57.7% (SD = 11.5%) without air injection, to 83.0% (SD = 10.6%) with air injection. Deep stromal air injection delineates the pre-Descemet space, allowing deeper radial incisions with the ab interno radial keratotomy.


Sliding flap of conjunctival limbus to prevent recurrence of pterygium.

Several techniques have been advocated for the excision of a pterygium: bare sclera, conjunctival flaps, free conjunctival graft, and labial mucous membrane graft. Twenty eyes were treated with a sliding flap of limbal conjunctiva into the scleral bed of the excised pterygium, using 7-0 and 8-0 Vicryl sutures. Corticosteroids and tear substitutes were administered postoperatively. There was one recurrence in the 20 eyes performed with 1 year follow up. Recurrence was limited to that of 5% (1 case out of 20). Postoperative inflammatory reaction was minimal.


A granny-style slip knot for use in eye surgery.

An adjustable knot for use in ocular surgery is described herein. The first part of the knot is a granny knot, which allows tension to be adjusted. The advantages of this knot are: 1) ease of tying; 2) adjustability; and 3) small size of the knot.


Intrastromal photorefractive keratectomy with a new optically coupled laser probe.

Intrastromal photorefractive keratectomy is a new procedure in which compact linear or area regions of the corneal stroma can be vacuolized, yielding changes in corneal curvature. Diffraction-limited 1064-nanometer light pulses from a high rep rate Q-switched Nd-YAG laser were coupled through novel means into a probe with index-matched optical contact with the cornea. The resulting extremely reduced focal region initiated a plasma point that was free of shock front effects where tissue was reduced to liquid. This probe process was applied to the corneas of eye-bank eyes, and to living rabbit and primate eyes. The refractive effects were evaluated with slit-lamp microscopy, keratoscopy light and electron microscopy. Refractive effects similar to refractive keratotomy were observed immediately after treatment. Intrastromal highly localized vacuolized regions were observed at the depth of focus with variability of only 20 microns. The plasma point vacuoles were about 100 microns in diameter. Stromal material that occupied the vacuole space appeared completely reduced to liquid. The transition region between vacuole and normal tissue was less than 0.5 microns. The treatment vacuoles disappeared to the unaided eye 24 to 48 hours after treatment. Corneal refractive power can be achieved with intrastromal keratectomy.


The variability of urinary protein and creatinine excretion in patients with gestational proteinuric hypertension.

To determine the variability of protein excretion in patients with proteinuric hypertension and the accuracy of either a urinary protein/creatinine ratio or a Multistix examination for the estimation of a 24 h protein excretion. An indwelling urinary catheter was placed for 24 h and successive 8 h specimens examined. A tertiary referral hospital in Cape Town, South Africa. 22 women with significant proteinuria in pregnancy were studied. The urine volume, protein excretion and creatinine excretion in eight hourly periods were measured. Multistix examination of each specimen was recorded. A large coefficient of variation in urine volume (41%), amount of protein excreted (44%) and the amount of creatinine excreted (22%) in the eight hourly specimens were noted. The protein creatinine ratio did not accurately predict the 24 h protein excretion. The Multistix examination was less accurate with increasing amounts of proteinuria. The amount of creatinine excreted correlated with the volume of urine passed (r = 0.43). The analysis of a 24 h specimen or urine for protein excretion remains the best method of monitoring proteinuria in pregnancy. The amount of creatinine excreted in 24 h cannot be used as an index of completeness of collection of the 24 h specimen.


Prepregnancy counselling: experience from 1,075 cases.

To assess the activity of a prepregnancy counselling clinic in terms of investigations, counselling, treatment and subsequent pregnancy outcome. Review of 1,075 couples attending over a nine year period. University Hospital offering a tertiary referral service for fetal medicine. Couples referred to the clinic from a variety of sources. Categories of referral, value of diagnostic tests, and subsequent pregnancy outcome. The main categories of referral were: previous miscarriage (44.4%); previous fetal abnormality (19.6%); chronic maternal disease (22.3%); and others (13.7%). Routine investigations produced a low yield of abnormality (1%), in contrast to investigations selected for specific reasons (12%). Subsequent pregnancy outcome, which was unaltered in either the previous miscarriage or fetal abnormality groups, did improve in the chronic maternal disease group. This study does not prove the value of prepregnancy counselling. However, it does illustrate the importance of making an accurate assessment of previous problems and current health as a means of determining both maternal and fetal risks in a subsequent pregnancy, a process which seems to lead to an improved outcome within selected groups. The importance of continuity of care in all couples, especially when there has been a previous adverse pregnancy outcome is emphasized.


The effect of pH on release of PGE2 from vaginal and endocervical preparations for induction of labour: an in-vitro study.

To study the effect of pH and precoating with obstetric cream on the release of prostaglandin E2 (PGE2) from commercially available triacetin and starch based gels, lactose based vaginal tablets and sustained release hydrogel polymer pessaries in-vitro. A prospective observational study. PGE2 preparations held in dialysis bags were placed in Ringers lactate buffer and release of PGE2 into the buffer was measured over 8-12 h by radioimmunoassay. The hydrogel polymer pessary was also assessed after precoating with obstetric cream. In-vitro PGE2 release at pH 7.4, pH 5.4 and pH 3.4. RESULTS The gel preparations provided rapid and reliable release, while the lactose based vaginal tablet provided much lower release of PGE2 with sudden and variable release occurring after 5-8 h, an effect which was enhanced at low pH. With the triacetin gel preparation, release of PGE2 was reduced at lower pH, while the starch based gel appeared to provide optimal release at pH 5.4. The hydrogel polymer pessaries provided linear release in-vitro and this was reduced at pH 3.4. In addition, precoating the sustained release hydrogel polymer pessaries with obstetric cream virtually abolished release of PGE2. As the vagina is normally acid, these results suggest that vaginal pH could influence PGE2 release and this may result in variable clinical responses. In view of this, pH should be taken into account in the development of preparations for clinical use. Furthermore, the use of obstetric cream should be avoided when administering PGE2 preparations for induction of labour.


The efficacy of phenytoin in relation to serum levels in severe pre-eclampsia and eclampsia.

To investigate the efficacy of phenytoin in relation to total and free serum levels in patients with severe pre-eclampsia and eclampsia. Prospective descriptive study. Labour Ward, King Edward VIII Hospital, Durban, South Africa. Tertiary referral centre serving an underprivileged community. Eleven patients admitted with a hypertensive crisis. Four patients had eclampsia and 7 had impending eclampsia. Free and total phenytoin levels; efficacy of phenytoin as an anticonvulsant and side-effects of therapy. Although total phenytoin levels were within the therapeutic range, free phenytoin levels were abnormally high in all patients. Three patients (2 with eclampsia and 1 with imminent eclampsia) each had a seizure after phenytoin treatment had been initiated. Neither total nor free phenytoin levels were good predictors of seizure control. It is postulated that the poor performance of phenytoin as an anticonvulsant in severe eclampsia may relate to inadequate distribution of the drug to the brain as a result of cerebral oedema and poor cerebral perfusion rather than paradoxical seizure activity associated with high free phenytoin levels.


Spontaneous resolution of pre-eclampsia-related thrombocytopenia.

To observe the spontaneous resolution of pre-eclampsia-related thrombocytopenia. A retrospective study. High Risk Pregnancy Unit, John Radcliffe Maternity Hospital, Oxford. Thirty women with pre-eclampsia complicated by the HELLP/ELLP syndrome who did not receive any specific treatment for their thrombocytopenia. Serial platelet counts throughout labour and the puerperium until the platelet counts returned to levels above 100 x 10(9)/l. Time taken from delivery and platelet nadir for platelet counts to return to levels above 100 x 10(9)/l. The rate of recovery from the platelet nadir was measured by the slope of the serial platelet counts plotted against time. The mean time until platelet count exceeded 100 x 10(9)/l was 67 h (SD 25) after delivery and 44 h (SD 17) from the platelet nadir. All women had counts above 100 x 10(9)/l by 111 h after delivery, and by 88 h after the platelet nadir. Although the time to recovery appeared to depend on the degree of thrombocytopenia, the rate of resolution did not. These data can be used as a guide by clinicians as to the expected time course for postpartum resolution of pre-eclampsia-related thrombocytopenia.


Pre-eclampsia and trisomy 13.

To assess the reported association between field trisomy 13 and maternal pre-eclampsia. A retrospective case-control study. Twenty-five women who gave birth to trisomy 13 infants in southwest England between 1971 and 1989; 38 women who gave birth to trisomy 18 infants in the same region over the same time and 50 women with normal karyotype infants matched for age, parity, and date of delivery with the trisomy 13 group. The medical records of all the women in the three groups were analysed for evidence of pre-eclampsia. Four different thresholds of pre-eclampsia were used. The incidence of pre-eclampsia was compared between the three study groups and analysed separately for primigravid and multigravid women. The incidence of pre-eclampsia in pregnancies complicated by trisomy 13 was significantly higher than the incidence in the trisomy 18 and the normal karyotype control groups. This association was more pronounced in primigravid pregnancies. This, the largest survey of trisomy 13 and pre-eclampsia to date, suggests an association between the two conditions. It also supports the argument for a fetal factor in the pathogenesis of pre-eclampsia. We speculate on how genes encoded on chromosome 13 may be responsible.


Transfer and metabolism of platelet-activating factor by fetal membranes, amnion and chorio-decidua.

To determine the metabolism of 3H-Platelet-activating factor (3H-PAF) during transfer through human fetal membranes. 3H-PAF was added to the fetal side of cultured intact fetal membranes, amnion and chorio-decidua obtained from three pregnancies ending in elective caesarean section. Radioactivity was measured on both sides of the tissue, and in the tissue itself. In some experiments, the metabolism of 3H-PAF was assessed by thin-layer chromatography. Very little 3H-PAF crossed the intact fetal membrane (< 2%) during 24 h of culture. Most of the 3H-PAF which accumulated in the membrane was converted to a range of metabolites in the chorio-decidua. These results suggest that PAF in amniotic fluid may not reach the decidua, and therefore is unlikely to be involved in the control of prostaglandin production from this tissue.


The importance of serial biophysical assessment of fetal wellbeing in gastroschisis.

To review antenatal and intrapartum assessment of pregnancies complicated by gastroschisis. Retrospective descriptive study. University College Hospital, London. 24 consecutive cases of gastroschisis between 1986 and 1991. The gestational age at sonographic diagnosis was 20.3 weeks (SD 6.77) and at birth was 36.5 weeks (SD 2.06). There were 21 live births, all with good surgical outcome. There were 16 vaginal deliveries and eight caesarean sections. The elective sections were for oligohydramnios and dilated bowel (1) and clinically suspected growth retardation (1); the intrapartum caesarean sections were for fetal distress (4) and premature breech presentation (2). There were six with dilated gut on ultrasound; one of these ended in a stillbirth. There was a significant association between gut dilatation and caesarean section for fetal distress (P = 0.004). There was also a significant association between meconium staining and fetal distress (P = 0.021). Of these babies, 46% were < or = third centile for corrected birth weight. While half of the babies with gastroschisis were small for gestational age at birth, reliable antenatal prediction of birth weight is difficult. Gut dilatation may be an indicator of either antenatal or intrapartum fetal distress, but does not correlate with poor neonatal surgical outcome. We suggest close antenatal surveillance of fetal wellbeing in all cases of gastroschisis because, in addition to growth retardation, many show some evidence of fetal distress and 12.5% end in stillbirth, even when appropriately grown.


The prognostic value of fetal ultrasonography before induction of labour.

To investigate whether ultrasound examination of the fetus and amniotic fluid before induction of labour can provide useful prognostic information about the course of labour and mode of delivery. A prospective observational study. The delivery suite of St Mary's Hospital, London. 101 women undergoing induction of labour. MEASURED VARIABLES: Biparietal diameter, head circumference, abdominal circumference, occipital position, amniotic fluid volume and umbilical artery Doppler velocimetry waveforms. The outcome of labour was assessed in terms of the induction delivery interval, the mode of delivery and the incidence of abnormal cardiotocograms in labour. Seven women were delivered by emergency caesarean section early in the first stage of labour because of a significant abnormality of the fetal heart trace and these pregnancies were characterized by small fetal abdominal circumference measurements. Marked oligohydramnios was also noted in five of these seven subjects. Small or average size babies who were surrounded by an adequate volume of amniotic fluid tended to be born spontaneously, whereas the majority of operative deliveries for failure to progress in labour were associated with fetal abdominal circumference measurements > or = 340 mm. The mean Bishop score of women before labour who delivered spontaneously was not significantly different from the scores of women who had a forceps delivery or caesarean section. Abnormal cord Doppler waveforms were observed in only one instance. In women undergoing induction of labour, the measurement by ultrasonography of two variables (fetal abdominal circumference and amniotic fluid volume) may allow the prospective identification of pregnancies at increased risk of fetal distress or dystocia. If these findings can be replicated in early spontaneous labour than more rational utilization of resources may be possible in hospital based obstetric practice.


Long term follow up of women after hysterectomy with a history of pre-invasive cancer of the cervix.

A long term review of women after hysterectomy with a history of pre-invasive carcinoma of the cervix. 193 women had cervical intra-epithelial neoplasia and two had adenocarcinoma in situ either at hysterectomy or at previous cone biopsy. These were followed up by annual cytology. South Glamorgan Health Authority. Of 195 women who had a hysterectomy, 143 have been followed up cytologically for more than 10 years and 43 for more than 20 years: a total of 2800 women years of experience. Timing of abnormal smears. A detailed review of the five women with abnormal smears. The estimated percentage of women who remain negative is 98% at five years, 98.4%, at 10 years and 96.5% at 20 years. Cytological screening of all women who had a hysterectomy with a history of CIN is indicated for the first two years after hysterectomy. Thereafter the estimated incidence of 0.7 per 1000 women years is higher than the general population but it is not a sufficient reason to screen more frequently. We recommend screening for the carcinoma of the vagina to be every three years which is the same screening frequency as for cervical carcinoma in the general population.


Transcervical resection of the endometrium: a review of 400 consecutive patients.

To assess the efficacy of transcervical resection of the endometrium (TCRE) in women presenting with menstrual disorders. A retrospective audit of 400 patients. The Department of Gynaecology, St John's Hospital, Chelmsford, Essex. 400 consecutive referrals with various bleeding disorders which were suitable for treatment with TCRE. TCRE, either partially or completely. Patient satisfaction with procedure at 4 months. The procedure was initially recorded as a failure if any further therapy was required but satisfaction after a second procedure was assessed. 432 procedures were performed in 400 women. Major operative complications were rare with two (0.46%) uterine perforations, four (0.93%) primary haemorrhages requiring Tamponade to control bleeding and one (0.23%) secondary haemorrhage requiring hysterectomy to control it. Glycine toxicity was not clinically apparent. 85% were satisfied after the initial TCRE and 92% were satisfied if the procedure was repeated. TCRE is an advance in the management of menstrual disorders. Extensive training is required to minimise complications. The lack of long term follow-up is its major deficiency but this will be rectified in the future.


Randomised comparative study in 217 women of three disposable plastic IUCD thread retrievers.

To assess the relative efficacy of three disposable plastic instruments in the retrieval of 'missing' IUCD threads. A prospective randomised comparative single centre study. Family Planning Clinic in London, UK. 217 of 350 IUCD users referred to the research team with 'missing' IUCD threads entered the study. All women initially underwent exploration of the endocervical canal with Spencer Wells forceps. When this procedure did not retrieve the threads, the patients were entered into the study. A maximum of two randomly chosen plastic IUCD thread retrievers were then used in any one patient to explore the uterine cavity and capture the 'missing' threads. The order in which the two retrievers were employed was also determined at random. Four separate entries into the uterine cavity were permitted with each instrument, the endocervical canal being explored with Spencer Wells forceps after each retraction of the instrument to identify the possible descent of the threads. Threads brought down beyond the external cervical os, or threads brought to within the endocervical canal and then grasped by Spencer Wells forceps. In approximately 40% of all patients, the threads were retrieved with Spencer Wells forceps alone and a further 40% with the disposable plastic retrievers. About 5% had no retrievable threads, and only 2.5% of the referred patients required general anaesthesia for removal of their IUCD. The analysis of the comparative trial was confined to the 197 patients with retrievable threads which could not be brought below the external os with Spencer Wells forceps. The first plastic retriever used was successful in 50% of patients. The Retrievette (59%) and the Emmett (53%) performed better than the Mi-Mark Helix (37%) in this study. The difference was statistically significant (P = 0.03) and the 95% confidence interval for the difference of the Mi-Mark Helix from the other two retrievers was 4% to 33%. This retrieval rate for the Mi-Mark Helix was much worse than in previously reported studies, though one doctor did have a better success rate with this retriever. The success rates, using a second plastic retriever randomly chosen from the two not used in the first attempt, were almost identical to those observed with the first retrievers: 63%, 56% and 36%. The success rate did not appear to be influenced by the length of thread, day of cycle, device type or parity. The success of the second retriever tried did not seem to be influenced by the retriever that had failed previously. Based on our experience, the initial exploration of the endocervical canal with Spencer Wells forceps is invaluable. If this simple manoeuvre fails to retrieve the 'missing' threads, either the Retrievette or the Emmett thread retrievers are useful tools in general practice or in the family planning clinic setting.


Treatment of oral cancer by interstitial irradiation using iridium-192.

Sixty-seven patients with squamous cell carcinoma of the oral cavity were treated by implantation of radio-active iridium wire between 1977 and 1986. The results are presented in the hope of providing a comparison with those of primary surgical management. The crude 5-year survival rates were 61% for T1, 74% for T2, and 37% for T3 tumours. The major causes of death were uncontrolled tumour in the neck and intercurrent disease. Seven of 52 patients with T1 or T2 tumours (13%) developed local recurrence at the primary site; five were salvaged surgically, for an ultimate failure rate of 4%. The ultimate failure for a group of 15 T3 tumours was 47%. The only morbidity was a 31% incidence of soft tissue ulcers occurring during the first 18 months after treatment, none of which persisted. Elective external beam radiotherapy to the clinically negative neck significantly reduced the incidence of overt lymph node metastases.


Prevalence of post-traumatic stress disorder in patients with chronic idiopathic facial pain.

34 patients with chronic idiopathic orofacial pain were assessed by a structured clinical interview for diagnosis of mental disorders according to the Diagnostic and Statistical Manual for Mental Disorders (DSM-III-R). Five (15%) had a history of post traumatic stress disorder (PTSD) which coincided with the pain onset. The majority of these PTSD sufferers also had a personality disorder. The implications of these findings in the diagnosis and management of post-traumatic chronic TMJ pain syndromes is discussed.


Waiting list hurdles and the role of the pre-surgical booking clinic.

Patients requiring surgery have two main hurdles to cross--long waiting lists and the risk of late cancellation when dates become available. A study was conducted to investigate the inconvenience caused by late cancellation, and to show how the pre-surgical assessment clinic can be utilised to reduce the dissatisfaction and disappointment of the current waiting list system in surgery.


Le Fort I maxillary osteotomy: is it possible to accurately produce planned pre-operative movements?

The planned preoperative maxillary movements for five groups of patients requiring orthognathic surgery were prospectively compared to the actual surgical movements achieved in the operating theatre. There was a very poor success rate in achieving predicted movements in all the patient groups. There is a need to test and implement a reliable method of assisting the surgeon in spatially orientating the jaws on the operating table.


Experience with ITI osseointegrated implants at five centres in the UK.

Experience with the two-part ITI titanium implant system at five centres in the UK is reported. A total of 461 implants were inserted in 176 patients, who received 189 prostheses. Criteria for the assessment of success following implantation are listed. Results over a 3-year period showed a success rate of 94% when implants were used for mandibular overdentures and crown and bridge prosthetics. A lower success rate in the edentulous maxilla was recorded.


Abnormal bone masses in Klippel-Feil syndrome.

Five female patients with Klippel-Feil syndrome (KFS) are presented with abnormal bony masses in the mandibular ramus region. The features of KFS are described with assessment and treatment of the five patients. Although congenital duplication of mandibular rami in KFS has been previously documented, we believe this is the first series of patients with this deformity.


Equipment and methods for simple sensory testing.

Four simple tests which can be used for routine sensory testing following trigeminal nerve injuries are suggested. The methods for constructing the equipment needed for these tests are described.


The origin of the temporalis muscle flap.

This paper explores the origin of the temporalis muscle flap which has been attributed to Golovine, a Moscow ophthalmic surgeon, who described a forehead skin transposition flap. Small temporalis muscle transpositions were used in surgery for TMJ ankylosis, but the use of the majority of the muscle for reconstruction of facial defects was first described by Sir Harold Gillies during the 1914-18 war.


Traumatic cavernous carotid aneurysm resulting in blindness.

A case of traumatic aneurysms of the cavernous internal carotid artery which resulted in blindness is presented. This condition would appear to be a rare consequence of maxillofacial trauma, although fistulae are relatively common. The reasons for this apparent paradox, the difficulty of diagnosis and the management are discussed.


Dermatofibrosarcoma protuberans of the scalp.

Dermatofibrosarcoma protuberans is an uncommon tumour of the dermis and rarely occurs on the scalp; there are few known predisposing factors. A case is described of such a tumour that occurred at the site of radiotherapy for a basal cell carcinoma. Histological characteristics, behaviour and management of dermatofibrosarcoma protuberans are discussed.


Lipoprotein profile of a Greenland Inuit population. Influence of anthropometric variables, Apo E and A4 polymorphism, and lifestyle.

Previously it has been reported that Greenland Inuit (Eskimos) from the Uummannaq district display low levels of plasma cholesterol and triglycerides and relatively high levels of high density lipoprotein (HDL) when compared with healthy Danish control subjects (Lancet 1971;1:1143-1146). Here we present data obtained in 1989 that show the following. In a group of 133 healthy adult Greenland Inuit from Nanortalik, the levels of plasma cholesterol and low density lipoprotein (LDL) cholesterol (6.39 and 4.39 mmol/l, respectively) were slightly higher than "normal" values found in western societies, whereas the HDL cholesterol level was markedly higher (1.64 mmol/l). Compared with most Caucasian populations, the Inuit population we studied exhibits a high apolipoprotein (APO)E*4 allele frequency (0.229), whereas the APOE*2 allele frequency was extremely low (0.015). In contrast to Caucasian populations, in the Inuit population the apoE polymorphism showed only a minor influence on the plasma lipid and (apo)lipoprotein levels, as evaluated by multiple regression analysis, with the exception of apoE levels. This absence of an effect could be explained by the low very low density lipoprotein (VLDL) plus intermediate density lipoprotein (IDL) cholesterol levels. The contributions of eicosapentaenoic acid and linoleic acid to the total amount of fatty acids in plasma cholesterol esters differed markedly from those reported in 1971 for another Greenland Inuit population (3.2% versus 15.8% and 49.5% versus 20.4%, respectively), thereby resembling values now found in the average western population. Even in those Inuit who reported exclusive consumption of the traditional Inuit diet (13% of the population), the fatty acid composition of the plasma cholesterol esters closely resembled the values measured in western populations.(ABSTRACT TRUNCATED AT 250 WORDS)


Chronic rejection of rat aortic allografts. III. Synthesis of major eicosanoids by vascular wall components and effect of inhibition of the thromboxane cascade.

We have previously demonstrated that rat aortic allografts from the DA (RT1a) to the WF (RT1v) strain develop chronic arteriosclerotic changes in the vascular wall after a short spontaneously reversible acute rejection episode. These changes, which are lacking in syngeneic DA-to-DA control grafts, are virtually identical with those observed in human allografts during chronic rejection. In this study we have investigated whether eicosanoids are involved in the generation of arteriosclerotic changes. Incubation of aortic wall rings in vitro and immunochemical assays demonstrated that the arteriosclerotic allografts synthesize significantly more thromboxane B2 (TxB2) but not 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) or leukotriene B4. The increased synthesis of TxB2 in the allografts persisted for at least 5 months after transplantation. Separate incubation of the two major components of the vascular wall, after microdissection of the intima and (media plus) adventitia, demonstrated that most of the synthesis of TxB2 during chronic rejection was due to the outer layer of aorta, presumably the inflammatory cells of the adventitia. In contrast, most of the 6-keto-PGF1 alpha was synthesized by the inner layer of the aorta, presumably the endothelial cells and the smooth muscle cells of the intima. Administration of 1 mg.kg-1 x day-1 of a specific TxA2 receptor inhibitor, GR32191B, to the recipient rat reduced the proliferative response of inflammatory cells in the adventitia by 30%, as detected by in vivo tritiated-thymidine (3H-TdR) labeling and autoradiography, but did not reduce the proliferative response of smooth muscle cells in the media and intima.(ABSTRACT TRUNCATED AT 250 WORDS)


Upper-body fat distribution: a hyperinsulinemia-independent predictor of coronary heart disease mortality. The Paris Prospective Study.

The Paris Prospective Study is a long-term investigation of the factors predicting coronary heart disease in a large population of middle-aged men. The first follow-up examination involved 7,152 subjects, who were natives of metropolitan France and were free of any cardiovascular history. At that time, the usual cardiovascular risk factors and plasma insulin levels were recorded. An index of body fat distribution, the iliac-to-thigh ratio, was entered into the list of predictive variables, despite the fact that it had been measured 1 year before the first follow-up examination. After 11 years of mean follow-up, 129 of the men had died of coronary heart disease. Univariate analysis showed that the iliac-to-thigh ratio (p < 0.0001) and plasma insulin level (both fasting [p < 0.003] and 2-hour postload [p < 0.02]), as well as the four major risk factors of coronary heart disease (age, smoking, blood pressure, and plasma cholesterol level) were significantly higher in subjects who died of coronary heart disease compared with those who had died of another cause or were alive at the end of follow-up. In multivariate stepwise logistic regression, the iliac-to-thigh ratio appeared as an independent predictor of coronary heart disease death, thereby causing the removal of fasting insulin level from the list of significant independent predictors. Nevertheless, in a model that entered 2-hour postload insulin in two classes (high or low), both the insulin level and iliac-to-thigh ratio were found as significant independent predictors.(ABSTRACT TRUNCATED AT 250 WORDS)


Mitogenic activity of interferon gamma on growth-arrested human vascular smooth muscle cells.

Interferon gamma (IFN-gamma) is a multifunctional lymphokine secreted by activated T lymphocytes, which are found in atherosclerotic lesions. IFN-gamma has been reported to suppress the proliferation of vascular smooth muscle cells (SMCs). However, as we report in this paper, IFN-gamma is mitogenic for vascular SMCs under certain circumstances. Recombinant human IFN-gamma (1-100 units/ml), in a dose-dependent fashion, stimulated cell multiplication and [3H]thymidine and 5-bromo-2'-deoxyuridine incorporation into DNA by cultured arterial SMCs that had been growth arrested by culturing in 1% plasma-derived serum for 5 days. IFN-gamma also accentuated the mitogenic activity of platelet-derived growth factor (PDGF)-BB. A time-course study revealed that there was a time lag of 4-6 hours between the G1-->S transition of quiescent SMCs stimulated by IFN-gamma and that of SMCs stimulated by PDGF-BB. A synergistic effect of IFN-gamma on the mitogenicity of PDGF became apparent after a similar time lag, suggesting that the IFN-gamma-related mitogenicity is mediated by a substance(s) secreted by IFN-gamma-treated SMCs. In fact, conditioned medium of IFN-gamma-treated SMCs was mitogenic for SMCs. Mitogenic activity in the conditioned medium was also detected by an assay using Swiss 3T3 cells, which originate from mice and, therefore, are not responsive to human IFN-gamma. The production of the mitogenic factor was blocked by anti-IFN-gamma antibody. Mitogenicity of the conditioned medium was not eliminated by addition of neutralizing antibody against PDGF, indicating that any autocrine growth factor(s) secreted by IFN-gamma-treated SMCs was not PDGF.(ABSTRACT TRUNCATED AT 250 WORDS)


Aortic permeability to LDL as a predictor of aortic cholesterol accumulation in cholesterol-fed rabbits.

The aim of this study was to investigate the possibility that the permeability characteristics of the arterial wall are related to the development of atherosclerosis. The in vivo regional variation of aortic permeability to iodinated human low density lipoprotein (LDL) in normal rabbits was compared with the regional variation in aortic cholesterol accumulation in cholesterol-fed rabbits. Aortas were divided into the aortic arch, thoracic aorta, and abdominal aorta, and each of these three parts was further subdivided into four segments of similar size. The permeability to LDL was 40 +/- 7 nl.cm-2.hr-1 (mean +/- SEM, n = 11) in the most proximal segment of the aortic arch and decreased throughout the length of the aorta to 3 +/- 1 nl.cm-2.hr-1 in the most caudal segment of the abdominal aorta. In such normal rabbits the aortic cholesterol content was similar in all 12 arterial segments at 0.08 +/- 0.005 mumol/cm2 (mean +/- SEM, n = 3 x 12). Aortic cholesterol accumulation was determined in other rabbits with an average plasma cholesterol level of 32 +/- 1 mmol/l for 96 days; the cholesterol content in the most proximal segment of the aortic arch was 2.7 +/- 0.5 mumol/cm2 (mean +/- SEM, n = 11) and decreased with increasing distance from the heart to 0.17 +/- 0.03 mumol/cm2 in the most caudal segment of the abdominal aorta. Linear regression analysis showed a close positive association between the permeability to LDL of a given aortic segment and the cholesterol accumulation in that same aortic segment after cholesterol feeding (r2 = 0.96, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)


LDL particle size distribution. Results from the Framingham Offspring Study.

Using 2-16% gradient gel electrophoresis, we examined low density lipoprotein (LDL) particle size in relation to plasma lipoproteins in 1,168 women and 1,172 men from the Framingham Offspring Study. In addition, we studied the effect of dietary intake on LDL size in a subset of the population. Seven LDL size peaks were identified, with the largest, LDL 1, being found in the density range 1.019-1.033 g/ml; LDL 2 and LDL 3 in d = 1.033-1.038 g/ml; LDL 4 and LDL5 in d = 1.038-1.050 g/ml; and the smallest, LDL 6 and 7, in d = 1.050-1.063 g/ml. Seventy-seven percent of the population had one major and at least one minor LDL peak. Secondary LDL peaks accounted for 23% of the total LDL relative area, based on laser scanning densitometry. LDL size distribution was skewed toward larger LDL particles in women (prevalence of LDL 1, 30% and of LDL 2, 31%), whereas men exhibited a more symmetric distribution (prevalence of LDL 3, 42%). The prevalence of small (< 255 A), dense (d > 1.038 g/ml) LDL particles 4-7 was 33% in men, 5% in premenopausal women, and 14% in postmenopausal women. In agreement with previous reports, small, dense LDL particles were significantly (p < 0.0001) associated with increased triglyceride and apolipoprotein (apo) B levels and decreased HDL cholesterol and apo A-I levels. In addition, we found a significant (p < 0.0001) association between LDL cholesterol and LDL size. The highest LDL cholesterol levels were found among women with LDL 4 (148 mg/dl) and men with LDL 3-5 (138 mg/dl). In addition, the presence of LDL 3 or 4 as secondary peaks was significantly associated with higher LDL cholesterol levels, while smaller secondary LDL peaks were associated with higher triglyceride levels. We also found that compared with subjects with optimal LDL cholesterol levels (< 130 mg/dl), individuals with high-risk LDL cholesterol levels (> or = 160 mg/dl) had 1) a higher prevalence of LDL 3 and 4 (women only) and a lower prevalence of LDL 1 and 2 (women only) and 2) 11% higher LDL cholesterol to apo B ratios, even when matched for LDL particle size. Furthermore, low saturated fat and cholesterol intakes were significantly associated (p < 0.01) with smaller LDL particles. Therefore, the identification of small, dense LDL particles per se may not be a good indicator of coronary artery disease risk in population studies.(ABSTRACT TRUNCATED AT 400 WORDS)


Thrombogenicity and procoagulant activity of human mesothelial cells.

Cell seeding may decrease the thrombogenicity of implanted vascular grafts, but its application is hampered by the limited availability of autologous endothelial cells. We studied the interaction of alternate cells, human peritoneal mesothelial cells, with whole blood in a flow chamber. When citrated blood was perfused over mesothelial cells, platelet adhesion was seen on the intercellular matrix but not on the cells themselves. Perfusions with blood anticoagulated with low-molecular-weight heparin resulted in fibrin formation at the surface of mesothelial cells but not at the surface of human umbilical venous endothelial cells. At shear rates of 200 sec-1 fibrin deposition on the mesothelial cell surface increased during the first 5 minutes to 5.7 +/- 1.06 micrograms fibrin per square centimeter, whereafter these values stabilized. The procoagulant activity of cultured mesothelial cells was higher than that of peritoneal membrane studied ex vivo. However, cultured mesothelial cells incubated with polyclonal antibodies against tissue factor showed a significant decrease in procoagulant activity. We conclude that human peritoneal mesothelial cells may be used for cell seeding procedures, provided that their tissue factor expression can be controlled.


Polarized binding of lipoprotein lipase to endothelial cells. Implications for its physiological actions.

Lipoprotein lipase (LPL) that is associated with the luminal surface of capillary endothelial cells hydrolyzes circulating lipoprotein triglyceride molecules. Because LPL is synthesized by cells on the abluminal side of endothelial cells, LPL must contact both the abluminal as well as the luminal sides of the endothelium. To determine whether LPL interacts identically with apical (luminal) and basolateral (abluminal) sides of endothelial cells, we investigated binding, transport, and cellular uptake of LPL presented to each side of bovine aortic endothelial cell monolayers grown on semipermeable filters. When LPL was included in the medium on either the apical or basolateral side of the cells, a similar amount of LPL was found in the medium on the opposite side of the cells. Heat-inactivated LPL crossed the monolayers more rapidly in both directions. When cell surface LPL was assessed, more LPL bound to the apical than the basolateral endothelial cell surface. Release of cell surface-associated LPL was assessed with the use of heparin. Less heparin was required to dissociate apical-surface LPL. When LPL (4 micrograms/ml) was in contact with the apical surface for 1 hour, 32.8 +/- 4.9 ng LPL per 24-mm filter were internalized by the cells. If the LPL was in the basolateral medium, only 6 +/- 1.8 ng LPL were found inside the cells. Heat inactivation decreased LPL binding to cell surfaces and internalization by the cells. LPL interactions with the cells were also studied morphologically by using Texas Red (TR)-labeled LPL and confocal microscopy. More TR-LPL was associated with and internalized by the apical endothelial surface. Incubation of cells with TR-LPL in the basolateral medium led to accumulation of LPL on the apical surface, suggesting that the LPL was transported across the cells. Inclusion of TR-LPL on the apical surface did not lead to appreciable accumulation of LPL on the basolateral cell surface. Therefore, endothelial cells are polarized to accumulate LPL on the apical surface. In addition, more LPL is internalized from this side of the cells. We postulate that the polarity of endothelial cells allows LPL to collect at its physiological site of action, i.e., on the luminal surface.


Regulation of lipoprotein lipase secretion in murine macrophages during foam cell formation in vitro. Effect of triglyceride-rich lipoproteins.

Triglyceride rich-lipoproteins induce triglyceride accumulation in macrophages, leading to foam cell formation. The correlation between cell triglyceride accumulation and lipoprotein lipase (LPL) secretion in murine macrophages and the role that LPL plays in the accumulation process were examined. LPL secretion is defined as the extracellular LPL activity that accumulates during a 4-hour incubation of treated and untreated cells in a bovine serum albumin-containing RPMI-1640 medium. LPL secretion was suppressed (up to 70%) in a dose- and time-dependent manner when J774.1 cells were incubated with chylomicrons, very low density lipoproteins, and intermediate density lipoproteins but not with low or high density lipoproteins from normolipidemic and hypertriglyceridemic subjects. Oleic acid both suppressed LPL secretion and invoked triglyceride accumulation. Suppression of LPL secretion preceded gross triglyceride accumulation, was reversible, and was not the result of a reduction in LPL mRNA. P388D1 cells neither secreted LPL nor accumulated triglyceride. Inhibition of LPL secretion by tunicamycin in both peritoneal macrophages and J774.1 cells prevented a hypertriglyceridemic very low density lipoprotein-induced triglyceride accumulation, an effect that was counteracted by addition of exogenous LPL. The results suggest that 1) extracellular hydrolysis of lipoprotein triglyceride is a major factor in inducing foam cell formation and 2) LPL secretion may be regulated by cell energy needs, and when these needs are exceeded, LPL secretion is suppressed.


Familial correlations of HDL subclasses based on gradient gel electrophoresis.

We used nondenaturing polyacrylamide gradient gel electrophoresis to examine the familial correlations of high density lipoprotein (HDL) subclasses for 150 offspring in 47 nuclear families. The absorbance of protein stain was used as an index of mass concentrations at intervals of 0.01 nm within five HDL subclasses: HDL3c (7.2-7.8 nm), HDL3b (7.8-8.2 nm), HDL3a (8.2-8.8 nm), HDL2a (8.8-9.7 nm), and HDL2b (9.7-12 nm). Parent-offspring correlations were computed for two different characterizations of the parents: 1) by sex (i.e., mother versus father) and 2) by their relative values (highest versus lowest HDL). Sibling resemblance was assessed by using the intraclass correlations coefficient. Family members were significantly related for the following subclasses: HDL3c (sibling and father-offspring), HDL3b (sibling), HDL3a (sibling and mother-offspring), HDL2a (mother-offspring), and HDL2b (sibling, father-offspring, and mother-offspring). The offsprings' HDL3c and HDL2b values were more strongly related to their fathers' than to their mothers' values, whereas their HDL2a levels were more strongly related to their mothers' than their fathers' values. In addition, fathers' HDL2b levels were inversely correlated with the offsprings' HDL3b. The parents' HDL subclass levels were more strongly related to subclass levels of their younger (< or = 20 years) than their older offspring. Among all subclasses, HDL2b showed the strongest parent-offspring relation, with the parents' HDL values accounting for over 30% of the variance in offsprings' HDL2b.(ABSTRACT TRUNCATED AT 250 WORDS)


Activation of platelets in blood perfusing angioplasty-damaged coronary arteries. Flow cytometric detection.

Fluorescence-activated flow cytometry has been used to investigate platelet activation in blood flowing through atherosclerotic coronary arteries after sustaining mechanical damage induced by percutaneous transluminal angioplasty (PTCA). For flow cytometry, platelets and platelet-derived microparticles were identified by biotinylated anti-glycoprotein (GP) Ib monoclonal antibody (mAb) and a fluorophore, phycoerythrin-streptavidin. Activated platelets were detected by using a panel of fluoresceinated mAbs specific for activation-dependent platelet epitopes, including 1) activated GPIIb-IIIa complex (PAC1); 2) fibrinogen bound to platelet GPIIb-IIIa (9F9); 3) ligand-induced binding sites on GPIIIa (anti-LIBS1); and 4) P-selectin, an alpha-granule membrane protein expressed on the platelet surface after secretion (S12). The binding of antibodies to platelets was determined in blood that was sampled continuously via heparin-coated catheters from the coronary sinus in 1) patients before, during, and for 30 minutes after PTCA and 2) control patients undergoing coronary angiography without PTCA. Platelets in coronary sinus blood showed significant binding of mAbs that specifically detect activation epitopes associated with the GPIIb-IIIa complex (PAC1, anti-LIBS1, and 9F9) during and for 30 minutes after angioplasty in four of the five patients. The relative proportion of platelets positive for PAC1 and anti-LIBS1 increased from baseline values of 2.0 +/- 0.3% (mean +/- SD) and 2.0 +/- 0.5% to 18 +/- 14% and 28 +/- 14%, respectively, during PTCA or 30 minutes after PTCA (p < 0.01 in both cases). Binding with 9F9 was less prominent. The expression of P-selectin was detected in one of the five patients. By contrast, activation-specific mAbs failed to bind detectably with platelets obtained from 1) the peripheral blood during coronary angiography in eight patients or 2) coronary sinus blood obtained via catheter throughout control catheterization procedures in three patients or before PTCA in five. We conclude that circulating platelets become activated while flowing through PTCA-damaged stenotic coronary arteries and that this process of platelet activation is readily demonstrated by measuring the expression of activation-specific membrane GP epitopes by flow cytometric analysis.


Pituitary factors in blood plasma are necessary for smooth muscle cell proliferation in response to injury in vivo.

Intimal thickening in response to vascular injury is inhibited in animals previously subjected to hypophysectomy. We have investigated the nature and cell kinetics of this effect in a balloon catheter model of injury to the rat carotid artery. The ability of injury to stimulate [3H]thymidine labeling 48 hours after injury was almost completely eliminated in hypophysectomized (hypox) compared with control animals (0.1% versus 32.1%). Total DNA content of the developing neointima 14 days after injury was only 30% of the values found in ballooned carotid arteries of normal rats. If hypox rats were treated with recombinant human growth hormone, the proliferative response was not restored. There are two possible general explanations for the reduction of proliferative response in hypox animals: 1) that smooth muscle cells in the hypox animals have lost the ability to respond to the stimulus of injury or 2) that the ability of the smooth muscle cells to respond has not been reduced by prior hypophysectomy, but that the response itself requires the presence of pituitary-dependent factors. Transplantation experiments were performed in vivo to distinguish between these possibilities. Carotid arteries in inbred Lewis rats were excised 1 hour after balloon injury to give platelets the opportunity to adhere. These vessels were then transplanted from hypox into control animals and vice versa. At 48 hours, proliferation of smooth muscle cells in "control-to-hypox" transplants was 0.3% compared with 14.3% in "control-to-control" transplants, whereas vessels from hypox rats increased their indices to 4.8% if transplanted into control animals.(ABSTRACT TRUNCATED AT 250 WORDS)


LDL subclass phenotypes and triglyceride metabolism in non-insulin-dependent diabetes.

Plasma low density lipoprotein (LDL) comprises multiple discrete subclasses differing in size, density, and chemical composition. A common, heritable phenotype characterized by the predominance of small, dense LDL particles (LDL subclass phenotype B) is associated with relatively increased concentrations of plasma triglycerides, reduced levels of high density lipoprotein, and increased risk of coronary artery disease in comparison with subjects with larger LDL (LDL subclass phenotype A). Population studies have indicated that approximately 20-30% of adult men have phenotype B, and another 15-20% have LDL of intermediate size. The lipid changes in phenotype B are similar to those that have been observed in patients with non-insulin-dependent diabetes mellitus (NIDDM). In the present study, we have assessed LDL subclass phenotypes in normolipidemic men with NIDDM and in age-matched control subjects who had similar lipid levels. There was a greater than twofold increase in the percentage of individuals with the LDL B phenotype in the NIDDM subjects. The LDL B phenotype was associated with higher plasma triglyceride levels and a trend toward lower high density lipoprotein cholesterol levels compared with the LDL A phenotype in the NIDDM subjects, as has been previously observed in control groups. Indices of diabetic control, such as fasting and hemoglobin A1 levels, were similar regardless of LDL phenotype pattern, suggesting that glycemic control was not likely to account for the increase in the LDL B phenotype. In both control and NIDDM subjects, the clearance of triglyceride-rich lipoproteins was slowed in the subjects with the LDL phenotype B compared with those with the A phenotype.(ABSTRACT TRUNCATED AT 250 WORDS)


Altered susceptibility to in vitro oxidation of LDL in LDL complexes and LDL aggregates.

Low density lipoprotein (LDL) is known to form complexes with polysulfated compounds, like heparin, dextran sulfate (DS), and chondroitin sulfate. In particular, chondroitin 6-sulfate (C6S)-rich proteoglycans of the arterial intima can associate with LDL, resulting in accumulation of LDL in atherosclerotic lesions. Besides LDL complex formation, LDL self-aggregation has been recently suggested to play a role in atherogenesis. Oxidative modification of LDL has also been implicated as a factor in the generation of the atherosclerotic plaque. Assuming that LDL self-aggregation may alter the molecule's susceptibility to oxidative modification, we have studied the sensitivity of LDL in LDL a aggregates as well as in insoluble and soluble LDL-C6S, LDL-heparin, and LDL-DS complexes to in vitro oxidation by cooper ions. Complexing the LDL with C6S and heparin resulted in an increased susceptibility of LDL to in vitro oxidation, whereas the oxidation of LDL complexed with DS was unaffected. In great contrast to the oxidation of LDL in LDL complexes, the in vitro oxidation of LDL in LDL aggregates (self-aggregation by denaturation) was strongly reduced. The results suggest that complex or aggregate formation may alter the susceptibility of the lipoprotein to oxidative modification and finally its metabolic fate or biological activity.


Augmented arterial wall expression of type-1 plasminogen activator inhibitor induced by thrombosis.

Type-1 plasminogen activator inhibitor (PAI-1), the primary physiological inhibitor of endogenous plasminogen activators, modulates fibrinolysis, cell migration, and tissue repair. To determine whether genetic expression of PAI-1 is augmented in the walls of vessels exposed to thrombi but not to a direct physical insult such as electrical injury, we induced arterial thrombosis in rabbit carotid arteries with intraluminal surgical silk sutures and performed in situ hybridization for PAI-1 messenger RNA (mRNA) and immunohistochemistry for PAI-1 antigen at selected intervals. PAI-1 activity in plasma remained virtually constant. In contrast, PAI-1 mRNA increased in endothelial cells juxtaposed to thrombi, in smooth muscle cells adjacent to the neointima, and in macrophages surrounding the suture material. PAI-1 protein was detected in regions in which PAI-1 mRNA was expressed. The increased expression of PAI-1 mRNA colocalized with PAI-1 protein in the endothelium juxtaposed to thrombi may potentiate thrombosis by shifting the local balance between fibrinolysis and thrombosis toward thrombosis. Furthermore, it may alter vascular remodeling and predispose to stenosis after interventions such as angioplasty, in which local thrombosis cannot be avoided.


Increased lipid binding to thrombi in coronary artery disease. Findings in patients without premedication in native (not anticoagulated) test systems.

Thrombi and clots were produced from native (i.e., not anticoagulated) platelet-rich and platelet-poor plasma from patients with coronary artery disease and control subjects who had not taken any medication known to influence plasma lipids, coagulation, or platelet aggregation. The clotting times were recorded, and the lipid content of clots, thrombi, platelets, plasma, and high density lipoprotein was analyzed. Thrombi produced from native platelet-rich plasma were 46% heavier in coronary artery disease patients and contained about 20% more phospholipids and free cholesterol and about twice the amount of triglycerides and esterified cholesterol in both absolute and relative amounts with respect to the corresponding lipids of plasma plus platelets. The elevated content of lipids not only increases the size of the thrombi but also changes their quality because of an increased content in plasmatic lipids, as platelets contain only trace amounts of triglycerides and cholesterol esters. In agreement herewith, fibrinogen and maximal amplitude on the thrombelastogram were increased in coronary artery disease patients, whereas the thrombus-forming time and clotting times of platelet-poor and platelet-rich plasma were shortened, indicating accelerated coagulation and activation of platelets. Analysis of these results suggests a disturbed interrelation in coronary artery disease between lipids and hemostasis, in which platelets, high density lipoprotein, and lipoproteins rich in triglycerides and cholesterol esters may play a role.


A dose-finding study with remoxipride in the acute treatment of schizophrenic patients.

Two hundred and forty-two patients with acute schizophrenia were enrolled in a double-blind, comparative, dose-finding study of a novel antipsychotic, remoxipride. Remoxipride was evaluated in a low (30 to 90 mg), medium (120 to 240 mg) and a high (300 to 600 mg) dose range and compared with a haloperidol (15 to 45 mg), which was administered to a similar group of patients. The results support the antipsychotic effect of remoxipride, with maximum efficacy occurring at daily doses between 120 mg and 600 mg. Side-effects were more frequent at doses of remoxipride over 300 mg. In all groups, remoxipride caused consistently fewer extrapyramidal side-effects than haloperidol. The antipsychotic effect of remoxipride may be derived from specific blockade of dopamine D2 receptors in the mesolimbic tract. The findings also suggest that remoxipride may have a therapeutic effect on negative symptoms of schizophrenia.


The varied adult psychopathologies of children's behavior disorders.

Thirteen percent of the general population show the traits of emotional over-reactivity, emotional lability and impulsiveness that appear to be genetically transmitted. The troublesome manifestation of these traits can often be medically controlled, thereby reducing their costs to society.


Importance of maintaining normal nasal function in the cleft palate patient.

The external nose is a structure that provides prominence to the face. The internal nose is a paired nasal cavity that extends from the face to the pharynx. Turbinates are major structures within the lateral walls of the nose. They perform the major functions of the nose that include respiration, humidification, temperature regulation, and filtration of the inspired air. Conditions that obstruct the nose interfere with its optimal function. These range from acute or chronic infection to enlarged tonsils and adenoid tissue to nasal septal deviation. Surgeons caring for patients with clefts must have familiarity with nasal anatomy and function and conditions that alter them. Correction of these conditions may require medical and/or surgical treatment.


Navigation of the nose with flexible fiberoptic endoscopy.

The introduction of flexible fiberoptics into medicine revolutionized the evaluation and treatment of velopharyngeal dysfunction. In this paper, rigid endoscopy and flexible fiberoptic scopes are discussed, including their respective advantages and disadvantages. Anesthetic and anatomic considerations relative to the endoscopic procedure are presented. Transnasal endoscopy permits documentation of static and dynamic anatomy, information that may be fundamental for the understanding and treatment of patients with velopharyngeal dysfunction.


Dopamine receptor genes: new tools for molecular psychiatry.

For over a decade it has been generally assumed that all the pharmacological and biochemical actions of dopamine within the central nervous system and periphery were mediated by two distinct dopamine receptors. These receptors, termed D1 and D2, were defined as those coupled to the stimulation or inhibition of adenylate cyclase, respectively, and by their selectivity and avidity for various drugs and compounds. The concept that two dopamine receptors were sufficient to account for all the effects mediated by dopamine was an oversimplification. Recent molecular biological studies have identified five distinct genes which encode at least eight functional dopamine receptors. The members of the expanded dopamine receptor family, however, can still be codifed by way of the original D1 and D2 receptor dichotomy. These include two genes encoding dopamine D1-like receptors (D1 [D1A]/D5 [D1B]) and three genes encoding D2-like receptors (D2/D3/D4). We review here our recent work on the cloning and characterization of some of the members of the dopamine receptor gene family (D1, D2, D4, D5), their relationship to neuropsychiatric disorders and their potential role in antipsychotic drug action.


Nasal airway in breathing and speech.

Clefts of the lip and palate frequently produce nasal deformities that tend to reduce the size of the nasal airway. Approximately 70% of the cleft population have nasal airway impairment and about 80% "mouth-breathe" to some extent. Surgical correction of nasal, palatal, and pharyngeal structures may further compromise breathing. Type of cleft appears to affect airway size, with unilateral clefts demonstrating the smallest airway. Although a pharyngeal flap may further decrease airway size, some individuals do not notice a postoperative change because of airway compromise prior to flap placement. Speech is a modified breathing behavior that uses the respiratory system to provide an energy source and involves structures within the respiratory tract to modulate this energy into meaningful sounds. The oral, nasal, and pharyngeal structures that are affected by cleft lip and palate during breathing are often compromised for speech as well. The nasal airway plays an important role in controlling speech pressures when velopharyngeal function is impaired. A "good" nose for breathing is often a "bad" nose for speech under such circumstances.


Acoustic assessment of the nasal airway.

Instrumental assessment techniques are needed to acquire quantitative information concerning the form and function of the nasal cavity. Until recently, aerodynamic methods were virtually the only source of such information. Two additional instruments are now available that purport to provide information useful to clinicians interested in assessing nasal form and function. This paper describes both the Nasometer and the acoustic rhinometer. In addition, a more traditional measure involving acoustic analysis of nasal consonants is discussed. Both the known and potential benefits and limitations of each technique are discussed.


History of cleft lip nasal repair.

Surgery of the cleft lip nasal tip has lagged behind cleft lip surgery. In fact, in most early illustrations it was not even noted. Since the development of cosmetic rhinoplasty an endless array of techniques have been published. Unfortunately there are few studies of the gross anatomy.


Congenital clefts of the nose: principles of surgical management.

Congenital clefts of the nose are rare and highly variable. Because there are few examples, standard methods for treatment do not exist. Therefore each patient must be evaluated and managed individually with respect to anatomic elements, timing, and sequence of reconstruction.


Correction of the bilateral cleft lip nasal deformity: evolution of a surgical concept.

The origin of the nasal deformity of a bilateral complete cleft lip is both primary (deformation/malformation) and secondary (postoperative distortion). This is an interim report of a personal evolution from staged correction of the bilateral cleft nasal deformity to synchronous repair of the nose and the lip and premaxillary-maxillary clefts. The anatomic concept is that, because of the malpositioned alar cartilages, the columella only appears to be short in an infant with bilateral cleft lip. The technical stratagems to model the nose are: (1) alignment of the premaxilla and (2) anatomic placement of the alar cartilages with sculpturing of the overlying soft tissue.


Effects of orthognathic surgery on nasal form and function in the cleft patient.

Management of common problems of nasal airway obstruction in cleft and noncleft patients by the subnasal approach through the maxillary Le Fort I osteotomy are discussed. The effects of maxillary surgical repositioning on the esthetics of the nose and upper lip are presented, as well as the sequencing and timing of orthognathic surgery and nasal reconstruction in the cleft patient. Case presentations illustrate the results of this treatment approach.


Early and late treatment of unilateral cleft nasal deformity.

Surgical techniques have been developed to correct nasal deformity associated with unilateral cleft lip, alveolus, and palate. This deformity can be significantly corrected during the primary cleft lip repair, as performed by the technique described by the author. Secondary corrective procedures focus mostly on skeletal support and lining distortions as well as on rearrangements of lower lateral cartilages. At the final stage, esthetic appearance can be significantly improved by contour remodeling with the addition of cartilage and/or bony implants. Choice of surgical technique depends upon the severity of the deformity and the experience and proficiency of the surgeon. At the present time, correction of the nasal deformity associated with a unilateral cleft is an integral part of primary cleft lip repair and part of multidisciplinary management of cleft deformities.


Clinician activism and ethical restraints in providing treatment: preventive as opposed to reconstructive approaches.

There is seldom controversy when faced with treatment decisions for a child born with a birth defect. Occasionally, the situation arises in which a decision to withhold treatment must be made. Under most circumstances the responsibility for making such decisions rests with the child's parents or guardians, since it is generally felt that these individuals are the best advocates for the child's best interests. In order to make such difficult decisions, the parents are dependent upon the guidance and counseling of health professionals, especially the physicians most closely involved in each case. The ultimate decisions made by parents are dependent upon open and unambiguous communication with their children's clinicians as well as open communications among the caregivers themselves. The role of the clinician as an advocate for treatment and nontreatment of children is dependent upon clear unbiased communication and the desire to do what is in the best interest for each patient.


Management of major craniofacial anomalies: a pediatric perspective.

Ethical decision-making regarding complex congenital anomalies has evolved along with improvements in neonatal medical and surgical care, but also reflects a changed medical and social environment. The current process is complex and cumbersome, with no guarantee of consensus, and frequently leads to indecision and disagreement. Improvement of the process will require continued professional education, as well as better reconciliation of areas of ambivalence among professionals, families, and society.


Social and psychological effects of major craniofacial deformity.

This paper discusses the social and psychological experiences of patients with the most severe forms of craniofacial deformity. The paper concludes that individuals with the most severe forms of craniofacial deformities are at risk for experiencing social and psychological stress and for having their quality of life negatively impacted by the experience of having a facial deformity. Much of the stress experienced by these individuals is the result of the negative social response to their facial deformity. It is emphasized that many patients will not develop psychopathology, because of intervening personality and family factors that may ameliorate these negative social stressors. The excellent progress made in assessing, preventing, and treating the negative psychosocial impact of facial deformity is noted. Finally, in attempting to understand the impact of facial deformity on quality of life, emphasis is placed on the subjective evaluation of these factors by each individual patient and family.


Ethical and health policy issues in the treatment of children with major craniofacial deformities.

The advent of craniofacial surgery and neonatal intensive care has made it possible for children with serious craniofacial deformities to live and possibly to experience effective habilitation. These therapeutic innovations also raise important social and ethical issues that are rarely examined. This paper reviews the dilemmas that relate to the gatekeeper role for physicians, the impact of prenatal diagnosis, and the allocation of scarce fiscal and health resources to craniofacial care. The high degree of cost, the intense investment of medical resources, and the uncertain outcomes in the care of children with major craniofacial deformities, must be considered in the distribution of resources within a health system. The rationing of health resources is discussed as a future determinant of how care for major craniofacial deformities may be delivered in the United States.


Cytoplasmic Ca2+ oscillations in pancreatic beta-cells.

In the last 15 years it has been a growing interest in the cyclic variations of circulating insulin [46]. After the suggestion that this phenomenon may be due to oscillations of the beta-cell membrane potential [8,39], it was demonstrated that [Ca2+]i oscillates in the glucose-stimulated beta-cell with a similar frequency to that of pulsatile insulin release. The present review describes four types of [Ca2+]i oscillations in the pancreatic beta-cell. The slow sinusoidal oscillations, referred to as type-a, are those which most closely correspond to pulsatile insulin release. Although not affecting the properties of the type-a oscillations in individual beta-cells, the concentration of glucose is a determinant for their generation and further transformation into a sustained increase. Accordingly, cytoplasmic Ca2+ is regulated by sudden transitions between oscillatory and steady-state levels at threshold concentrations of glucose, which are characteristic for the individual beta-cell. This behaviour explains the observation of a gradual recruitment of previously non-secreting cells with increase of the extracellular glucose concentration [44]. However, it still remains to be elucidated how the sudden transitions between these three states translate into the co-ordinated slow oscillations of [Ca2+]i in the intact islet. Cyclic variations of circulating insulin require a synchronization of the [Ca2+]i cycles also among the islets in the pancreas. It is still an open question by which means the millions of islets communicate mutually to establish a pattern of pulsatile insulin release from the whole pancreas. The discovery that the beta-cell is not only the functional unit for insulin synthesis but also generates the [Ca2+]i oscillations required for pulsatile insulin release has both physiological and clinical implications. The fact that minor damage to the beta-cells prevents the type-a oscillations with maintenance of a glucose response in terms of raised [Ca2+]i reinforces previous arguments [54] that loss of insulin oscillations is an early indicator of type-2 diabetes. Further analyses of the [Ca2+]i oscillations in the beta-cells should include not only the mechanisms for their generation and subsequent propagation within or among the islets but also how modulation of their frequency affects the insulin sensitivity of various target cells. The latter approach may be important in the attempts to maintain normoglycemia under conditions minimizing the vascular effects of insulin supposed to precipitate hypertonia and atherosclerosis [70,71,77].


Analysis of the binding of polymyxin B to endotoxic lipid A and core glycolipid using a fluorescent displacement probe.

Dansylcadaverine, a cationic fluorescent probe binds to bacterial lipopolysaccharide and lipid A, and is displaced competitively by other compounds which possess affinity toward endotoxins. The binding parameters of dansylcadaverine for lipid A were determined by Scatchard analysis to be two apparently equivalent sites with apparent dissociation constants (Kd) ranging between 16 microM to 26 microM, while that obtained for core glycolipid from Salmonella minnesota Re595 yielded a Kd of 22 microM to 28 microM with three binding sites. The Kd of polymyxin B for lipid A was computed from dansylcadaverine displacement by the method of Horovitz and Levitzki (Horovitz, A., and Levitzki, A. (1987) Proc. Natl. Acad. Sci. USA 84, 6654-6658). The applicability of this method for analyzing fluorescence data was validated by comparing the Kds of melittin for lipid A obtained by direct Scatchard analysis, and by the Horovitz-Levitzki method. The displacement of dansylcadaverine from lipid A by polymyxin B was distinctly biphasic with Kds for polymyxin B-lipid A interactions corresponding to 0.4 microM and 1.5 microM, probably resulting as a consequence of lipid A being a mixture of mono- and di-phosphoryl species. This was not observed with core glycolipid, for which the Kd for polymyxin was estimated to range from 1.1 microM to 5.8 microM. The use of dansylcadaverine as a displacement probe offers a novel and convenient method of quantitating the interactions of a wide variety of substances with lipid A.


Persistence of increased cholesteryl ester in human skin fibroblasts is caused by residual exogenous sphingomyelinase and is reversed by phospholipid liposomes.

Human skin fibroblasts (HSF) were exposed to sphingomyelinase 50 or 5 mU/ml for 60 min, washed with 5 mM EDTA or 20% serum and with phosphate-buffered saline, and postincubated for 24 h in the presence of [14C]16:0 sphingomyelin (SP) liposomes. The recovery of up to 48% of label in the medium in ceramide provided evidence of persistence of sphingomyelinase activity. The rate of hydrolysis of [14C]16:0 SP remained the same irrespective of whether the liposomes were added immediately after the wash, or 3 or 6 h thereafter. In HSF labeled with [3H]cholesterol exposure to 50 mU/ml of sphingomyelinase for 60 min resulted in an increase in labeled cholesteryl ester (CE) at 6 and 24 h of postincubation. Addition of sphingomyelin liposomes reduced markedly the fraction of cellular labeled cholesteryl ester recovered after 24 h, while phosphatidylcholine liposomes were not effective. When the enzyme concentration had been reduced 5-20 fold the effect of sphingomyelin liposomes on cellular 3H-CE was evident already after 6 h of postincubation and some effect was seen also with phosphatidylcholine liposomes. Increase in the concentrations of SP liposomes to 150 micrograms/ml restored labeled cholesteryl ester to control values at 24 h. A significant reduction occurred also with 18:1 phosphatidylcholine liposomes but labeled cholesteryl ester remained 50-100% higher when compared with 18:1 or 18:2 SP. No correlation was seen between the rates of cholesteryl ester decrease and free cholesterol efflux into the medium. The inability to remove residual sphingomyelinase by regular washing procedures exaggerates and prolongs the recovery period of sphingomyelin during postincubation and delays the return of the cholesteryl ester pool to control levels. This can be counteracted by addition of phospholipid liposomes that can compete for the enzyme with the plasma membrane sphingomyelin and also substitute the hydrolyzed molecule in the plasma membrane to impede cholesterol flow to cell interior.


Structural elucidation of a novel phosphonoglycosphingolipid in eggs of the sea hare Aplysia juliana.

A novel phosphonoglycosphingolipid (AJPnGL) was isolated from eggs of the sea hare Aplysia juliana. The structure was determined to be Gal alpha 1-->2Gal beta 1-->4(2-aminoethylphosphonyl-->6)Glc beta 1-->1Cer by FAB/MS, 1H-NMR, hydrogen fluoride degradation, methylation analysis, partial acid hydrolysis and GC analysis of the component sugars, fatty acids and long-chain bases. The ceramide moiety of this lipid consisted of branched nonadeca-4-sphingenine and octadeca-4-sphingenine as main long-chain bases and palmitic acid and stearic acid as major fatty acids. Since the sugar chain (Gal alpha 1-->2Gal beta 1-->4Glc beta 1-->) and the ceramide moiety of AJPnGL were identical with those of the main neutral glycosphingolipid of eggs of A. juliana, the biosynthesis of AJPnGL may occur by the addition of 2-aminoethylphosphonate to the main neutral glycosphingolipid, Gal alpha 1-->2Gal beta 1-->4Glc beta 1-->1Cer.


Multiple phospholipase A2 activities in canine vascular smooth muscle.

Three phospholipase A2 activities from canine vascular smooth muscle were identified and characterized including: (1) a cytosolic calcium-independent phospholipase A2 which is activated by nucleotide di- and triphosphates; (2) a cytosolic calcium-dependent phospholipase A2 which is activated by physiologic increments in calcium ion concentration; and (3) a microsomal calcium-independent phospholipase A2 which was highly selective for plasmenylcholine substrate. Vascular smooth muscle cytosolic calcium-independent phospholipase A2 was activated 338% +/- 11 (X+S.E.; n = 15) by physiologic concentrations of ATP. Similar amounts of activation were also present utilizing other nucleotide di- and triphosphates (e.g., ADP, CTP, GDP and GTP) as well as non-hydrolyzable nucleotide triphosphate analogs (e.g., ATP-gamma-S, AMP-PNP and GTP-gamma-S). Vascular smooth muscle cytosolic calcium-dependent phospholipase A2 was purified 455-fold by sequential DEAE-Sephacel, Phenyl-Sepharose, Mono Q, hydroxyapatite and Superose 12 chromatographies. The partially purified calcium-dependent phospholipase A2 was activated by physiologic increments in calcium ion concentration (e.g., 1 microM) and possessed an apparent native molecular weight of 95 kDa, an acidic isoelectric point (pI = 4.8) and a neutral pH optimum (pH 7.0). Vascular smooth muscle microsomal phospholipase A2 activity was predominantly calcium-independent and was over six-fold selective for hydrolysis of plasmenylcholine substrate. Taken together, these results demonstrate the existence of three separate and distinct phospholipase A2 activities in vascular smooth muscle and identify ATP and calcium ion as independent modulators of discrete phospholipase A2 activities in vascular smooth muscle cells.


Structural characteristics of the ceramides of neutral glycosphingolipids in the human female genital tract--their menstrual cycle-associated change in the cervical epithelium and uterine endometrium, and their dissociation in the mucosa of the fallopian tube with the menstrual cycle.

In human cervical epithelium, uterine endometrium, and mucosa of the fallopian tubes, neutral glycosphingolipids were exclusively represented by the globo-series glycosphingolipids, such as CMH, LacCer, Gb3Cer and Gb4Cer, but the molecular species of their ceramide moieties were characteristically altered in the cervical epithelium and uterine endometrium during the menstrual cycle. Individual neutral glycosphingolipids in the cervical epithelium and the uterine endometrium at the follicular phase gave two bands on TLC, whereas those at the luteal phase displayed three bands, the third being the lower migrating one. Neutral glycosphingolipids migrating to the same positions as these lower-migrating bands were constantly detected in the mucosa of the fallopian tubes, independent of the menstrual cycle. The lower-migrating bands for the cervical epithelium and the uterine endometrium at the luteal phase were due to molecules mainly constructed of phytosphingosine with alpha-hydroxy fatty acids having chain lengths of 18-24 and 4-sphingenine with alpha-hydroxy fatty acids having chain lengths of 16-22, whereas those in the mucosa of the fallopian tubes were exclusively N-alpha-hydroxypalmitoyl 4-sphingenine.


In vivo phospholipid modification induces changes in microsomal delta 5-desaturase activity.

The phospholipid composition of rat-liver microsomes was modified by feeding weaning rats a choline-free diet. After 21 days, the phosphatidylcholine content decreased with a concomitant increment of phosphatidylserine and cholesterol. The bulk fluidity of the membrane decreased. Under these conditions, the delta 5-desaturase activity was diminished as well as the arachidonic-acid content of the membrane lipids.


Influence of an increased intake of linoleic acid on the incorporation of dietary (n-3) fatty acids in phospholipids and on prostanoid synthesis in rat tissues.

We investigated whether the amount of dietary linoleic acid (LA) (as corn oil) influences the incorporation of dietary eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) in tissue phospholipids and the prostanoid biosynthesis. Rats were fed four different levels of corn oil (at a total dietary fat level of either 2.5%, 5%, 10% or 20%); at each corn oil level, two groups of rats were supplemented with either EPA and DHA (200 mg/day) during 6 weeks, and compared with a group receiving oleic acid. The phospholipid fatty acid composition of liver, kidney and aorta showed, as expected, that the incorporation of EPA was highly suppressed by increasing the content of dietary linoleic acid in the diets. On the other hand, DHA was almost unaffected by the amounts of (n - 6) fatty acids in the diets. These results indicate that EPA levels but not DHA levels in tissue phospholipids were influenced by the competing dietary (n - 6) fatty acids. The tissue arachidonate content was similar under the various dietary linoleic acid conditions, but feeding EPA or DHA lowers the AA content. Moreover, the amount of dietary linoleic acid did not significantly influence the prostaglandin E2 (PGE2) production in stimulated aortic rings. However, PGE2 synthesis was significantly decreased in the groups treated with either EPA or DHA. Thromboxane B2 levels in serum followed a similar pattern. It is suggested that an increase of dietary (n - 3) PUFAs is more efficient to reduce (n - 6) eicosanoid formation than a decrease of dietary (n - 6) fatty acids.


High-level expression in Escherichia coli and rapid purification of enzymatically active honey bee venom phospholipase A2.

Bee venom phospholipase A2 (BV-PLA2) is a hydrolytic enzyme that specifically cleaves the sn-2 acyl bond of phospholipids at the lipid/water interface. The same enzyme is also believed to be responsible for some systemic anaphylactic reactions in bee venom sensitized individuals. To study the structure/function relationships of this enzyme and to define the molecular determinants responsible for its allergenic potential, a synthetic gene encoding the mature form of BV-PLA2 was expressed in Escherichia coli. This enzyme was produced as a fusion protein with a 6xHis-tag on its amino-terminus yielding 40-50 mg of fusion protein per 1 of culture after metal ion affinity chromatography. A kallikrein protease recognition site was engineered between the 6xHis-tag and the amino-terminus of the enzyme allowing isolation of the protein with its correct N-terminus. Recombinant affinity purified BV-PLA2 was refolded, purified to homogeneity, and cleaved with kallikrein, resulting in a final yield of 8-9 mg of active enzyme per 1 of culture. The enzymatic and immunological properties of the recombinant BV-PLA2 are identical to enzyme isolated from bee venom indicating a native-like folding of the protein.


Acyl-CoA: cholesterol acyltransferase and 3-hydroxy-3-methylglutaryl-CoA reductase in carp-liver microsomes: effect of cold acclimation on enzyme activities and on hepatic and plasma lipid composition.

Hepatic microsomal activities of acyl-CoA:cholesterol acyltransferase (ACAT) and 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, rate-limiting enzymes in cholesterol esterification and cholesterol synthesis, and the concentration sand compartmentalization of esterified and unesterified cholesterol, were studied in carp acclimated to 10 and 30 degrees C. Irrespective of acclimation temperature, carp-liver ACAT is characterized by an apparent Km-value for oleoyl-CoA of 11-15 microM and displays an optimum activity at pH 7.4. The enzyme activity is reduced approx. 2-fold upon preincubation of microsomes with alkaline phosphatase. Arrhenius plots of ACAT-activity are curvilinear, with curvatures considerably affected by the acclimation temperature of the fish. Carp HMG-CoA reductase has been characterized previously by Teichert and Wodtke ((1987) Biochim. Biophys. Acta 920, 161-170). When measured at 30 degrees C, ACAT activities from 30 degrees C- and 10 degrees C-acclimated carp are identical (approx. 6 pmol/min per mg protein), whilst 'expressed' HMG-CoA reductase activity (18.1 +/- 12.2 pmol/min per mg protein for 30 degrees C-acclimated carp vs. 159.8 +/- 106.6 pmol/min per mg protein for 10 degrees C-acclimated carp) is enhanced 9-fold in the cold environment. This disparity indicates that cold-acclimation results in a massive increase in the capacity for hepatic cholesterol synthesis relative to hepatic cholesterol esterification. At the same time, hepatic compositional analysis reveals identical contents of unesterified cholesterol in either groups of carp but significantly decreased (3-fold) amounts in cholesterol ester (and also in triacylglycerol, 4-fold) in cold-acclimated carp. Moreover, microsomal fractions display lower cholesterol to phospholipid ratios in the cold. In contrast, concentrations of either cholesterol fractions (and of triacylglycerols) in plasma--the mobile compartment for lipoprotein transport--do not differ in cold- and warm-acclimated carp. Based on current concepts of cholesterol metabolism, it is concluded that the cold-enhanced expression of hepatic HMG-CoA reductase activity is a homeostatic response directed against and compensating for a cold-induced but not yet characterized deficiency in hepatic cholesterol availability.


Metabolism of intravenously administered 7 alpha-hydroxycholesterol-3 beta-stearate in the hamster.

In order to investigate the metabolic fate of serum esterified 7 alpha-hydroxycholesterol, [4-14C]7 alpha-hydroxycholesterol-3 beta-stearate was synthesized from labeled cholesterol and administered to bile fistula hamsters intravenously. Bile samples were collected at every 20 min for 7 h. Radioactivity was detected in bile 40 min after the beginning of the infusion of the labeled compound and 56.5 +/- 5.7% (48.7-66.0%) of the administered radioactivity was recovered in bile during 7 h. The liver contained appreciable radioactivity (19.5 +/- 7.6% of the administered dose) at the time of sacrifice. Only a trace amount of radioactivity was detected in urine and blood. Cumulative recovery of the radioactivity was 76.3 +/- 8.6% (63.3-90.4%). Major radioactive metabolites in the bile samples were identified to be taurine- and glycine-conjugated cholic acid and chenodeoxycholic acid by radioactive thin-layer chromatographic analysis of the bile samples before and after enzymatic hydrolysis and 3 alpha-hydroxysteroid dehydrogenase treatment. The conversion was nearly complete and we could not detect neutral metabolites, such as the mother compound, free 7 alpha-hydroxycholesterol and bile alcohols, as well as glucuronidated or sulfated bile acids. It is concluded that serum esterified 7 alpha-hydroxycholesterol could be effectively taken up by the liver, hydrolyzed by cholesterol esterase and metabolized via the normal biosynthetic pathway to taurine- or glycine-conjugated primary bile acids to be excreted into bile.