Digital photography in orthodontics

A brief history of digital photography is provided along with a critical appraisal of the 'prosumer' and professional systems currently available. Recommendations are made as to the system best suited to current orthodontic practice.

Generation and refinement of peptide mimetic ligands for paratope-specific purification of monoclonal antibodies

Paratope-specific purification of antibodies has distinct advantages over conventional methods of antibody purification with respect to its capacity to isolate product of high purity and immunoreactivity. The present report addresses the problems of identifying peptide ligands for the purification of antibodies reactive with nonprotein antigens. Using an anti-steroid antibody as the model, a lead sequence that bound antibody was identified from a peptide phage display library. The minimum binding unit in this sequence was deduced using a series of truncated peptides synthesized on the heads of polyethylene pins. Replacement Net analysis of the minimum binding unit identified peptides with increased affinity for the antibody. The affinity-matured peptide mimotope bound antibody in solution. By molecular modeling the peptide was superimposable onto estrone-3-glucuronide localized in the crystal structure of the antibody binding pocket. In order to resolve problems of presentation posed by the reversal of orientation of the peptide on the affinity matrix compared with the pins, the mimotope peptide was synthesized in reverse sequence using d-amino acids. The resulting affinity matrix was effective for the purification of antibody. Eluted product demonstrated molecular homogeneity and high immunoreactivity. It is concluded that the combination of biological and chemical library techniques described provides a method for the generation and affinity maturation of mimotopes for antibodies against nonprotein antigens.

Relation between heart rate and pulse transit time during paced respiration

Pulse transit time (PTT) is a simple, non-invasive measurement, defined as the time taken from a reference time for the pulse pressure wave to travel to the periphery. PTT is influenced by heart rate, blood pressure changes and the compliance of the arteries, but few quantitative data are available describing the factors which influence PTT. The aim of this study was to investigate the relationship between the cardiac beat-to-beat interval (RR) and PTT, using paced respiration to generate changes in both variables. We analysed PTT and RR interval from 15 normal healthy subjects during paced breathing, and the cross-correlation function between PTT and RR was used to quantify their relationship. Over the 15 subjects, the maximum change in PTT ranged from 7 to 23 ms with a mean +/- standard deviation of 14 +/- 5 ms, and that in RR interval from 86 to 443 ms (241 +/- 102 ms). Examining changes over time, the best correlation (r = +0.69, p < 0.01) was obtained when PTT was advanced relative to RR, with a change in RR followed by a corresponding change in PTT 3.17 +/- 0.76 beats later. We conclude that there is a strong relationship between PTT changes and RR interval changes, but these changes are not in phase.

Word deafness presenting as a sudden hearing loss

Sudden hearing loss is a condition frequently seen in ENT departments and is usually due to otological pathology. We present a patient who described symptoms of a sudden inability to hear but who, on further questioning and investigations, had 'word deafness' due to bilateral temporoparietal infarcts. We discuss the clinical syndromes associated with these infarcts and the specific management of word deafness.

Doctor discontent. A comparison of physician satisfaction in different delivery system settings, 1986 and 1997

OBJECTIVE

To examine the differences in physician satisfaction associated with open- versus closed-model practice settings and to evaluate changes in physician satisfaction between 1986 and 1997. Open-model practices refer to those in which physicians accept patients from multiple health plans and insurers (i.e., do not have an exclusive arrangement with any single health plan). Closed-model practices refer to those wherein physicians have an exclusive relationship with a single health plan (i.e., staff- or group-model HMO).

DESIGN

Two cross-sectional surveys of physicians; one conducted in 1986 (Medical Outcomes Study) and one conducted in 1997 (Study of Primary Care Performance in Massachusetts).

SETTING

Primary care practices in Massachusetts.

PARTICIPANTS

General internists and family practitioners in Massachusetts.

MEASUREMENTS

Seven measures of physician satisfaction, including satisfaction with quality of care, the potential to achieve professional goals, time spent with individual patients, total earnings from practice, degree of personal autonomy, leisure time, and incentives for high quality.

RESULTS

Physicians in open- versus closed-model practices differed significantly in several aspects of their professional satisfaction. In 1997, open-model physicians were less satisfied than closed-model physicians with their total earnings, leisure time, and incentives for high quality. Open-model physicians reported significantly more difficulty with authorization procedures and reported more denials for care. Overall, physicians in 1997 were less satisfied in every aspect of their professional life than 1986 physicians. Differences were significant in three areas: time spent with individual patients, autonomy, and leisure time (P < or =.05). Among open-model physicians, satisfaction with autonomy and time with individual patients were significantly lower in 1997 than 1986 (P < or =.01). Among closed-model physicians, satisfaction with total earnings and with potential to achieve professional goals were significantly lower in 1997 than in 1986 (P < or =.01).

CONCLUSIONS

This study finds that the state of physician satisfaction in Massachusetts is extremely low, with the majority of physicians dissatisfied with the amount of time they have with individual patients, their leisure time, and their incentives for high quality. Satisfaction with most areas of practice declined significantly between 1986 and 1997. Open-model physicians were less satisfied than closed-model physicians in most aspects of practices.

The repeatability of superovulatory response and embryo recovery in sheep

Over an 8-year period, a total of 328 Scottish Blackface donor ewes were involved in a MOET program. They were synchronized with fluorogestone acetate sponges and superovulated with ovine FSH. After the onset of estrus, ewes were hand-mated and laparoscopic artificial insemination was performed with fresh semen 44-46 h after sponge removal. Embryos were recovered semi-laparoscopically on either Day 5 or Day 6 after insemination. Of the 328 donor ewes used, 222 ewes were supervoulated only once, while the remaining ewes were superovulated either twice (73 ewes), 3 times (26 ewes) or 4 times (7 ewes) at yearly intervals to generate a maximum of 474 records for subsequent analysis. There was no significant change in either mean ovulation rate or the mean number of embryos recovered per donor ewe at successive treatments. However, significant (P < 0.05 at least) effects of both year and donor ewe age existed for superovulatory response and number of embryos recovered, though only the effect of year was significant (P < 0.001) for percentage embryo recovery. Repeatability was significant (P < 0.05 at least) for both superovulatory response (r = 0.55, s.e. 0.055) and number of embryos recovered (r = 0.38, SE 0.074), but not for percentage embryo recovery (r = 0.04, SE 0.102).

Premature ovarian failure and the FMR1 gene

FMR1 is an X-linked gene that codes for an RNA binding protein. Expansion of a triplet repeat within exon 1 of the gene causes the fragile X syndrome, which is characterized by mental retardation and various physical anomalies. The triplet repeat in FMR1 can expand to varying degrees. Only the very large expansions in which there is concomitant methylation of the gene cause the fragile X syndrome. Expansions of between 50 and 200 repeats are premutations. Although premutations were originally perceived to be without phenotypic effect, there is now substantial evidence that female carriers of premutations are at increased risk of having early menopause. The FMR1 premutation is also associated with a significant number of cases ascertained because of idiopathic premature ovarian failure, particularly when ovarian failure is a familial trait. The molecular mechanism to explain the association between ovarian failure and premutations is unknown.

Assessment of computer-controlled inflation/deflation for determining the properties of PTCA balloon catheters with pressure-volume curves

Restenosis is a significant problem after percutaneous transluminal coronary angioplasty (PTCA), leading to further angina or even death. The mechanisms causing restenosis are not well understood and the effect of the angioplasty balloon on the artery wall is generally unknown. The aim of the research presented here was to assess the repeatability with which measurements of balloon pressure-volume characteristics could be made, to ensure that different balloons could be distinguished easily, an essential first step before the arteries themselves could be characterized. An inflation/deflation device was inflated with and without an attached balloon under computer control at a constant speed to 8 bar. The accuracy and repeatability of the technique was assessed within a single measurement session and between measurement sessions on six separate days. For each measurement session, four repeated inflations/deflations were carried out and the average was determined. Compliance (volume change/pressure change), inflation volume and pressure drop at 8 bar were determined for various balloon catheters of different size, type and manufacturer. The system repeatability SD for measuring volume without a balloon was +/- 0.0005 ml within a single measurement session, and +/- 0.002 ml between independent days. With an attached balloon the repeatability SD for measuring volume was +/- 0.001 ml within, and +/- 0.003 ml between days. Compliance was determined with a repeatability SD of +/- 0.16 microliter bar-1 within, and +/- 0.94 microliter bar-1 between days. The inflation/deflation device and technique employed allowed small changes in volume and compliance to be differentiated. The system also enabled differences due to the material characteristics for different PTCA balloons to be determined. Measured balloon characteristics were similar to the data given by manufacturers. This gives confidence in development of the technique for clinical use.

Production and characterization of 188Re-C595 antibody for radioimmunotherapy of transitional cell bladder cancer

Bladder cancer was responsible for >12,000 deaths in the United States in 1999. The high-molecular-weight glycoprotein MUC1 mucin is overexpressed on bladder tumors and represents a useful target for radioimmunoscintigraphy and radioimmunotherapy. We report on the production and initial tracer studies of a 188Re-antibody complex directed against this target and intended for intravesical radioimmunotherapy of superficial bladder cancer.

METHODS

188Re perrhenate was eluted from a 188W/188Re generator. C595 antibody was reduced with 2-mercaptoethanol and was labeled in the presence of stannous tartrate. The final reaction mixture contained high-molecular-weight contamination, which was removed from the complex using an affinity separation technique. The specificity and integrity of the antibody complex were tested by radioimmunoassay and size exclusion chromatography. Tumor localization was investigated using an ex vivo model in human cystectomy specimens. Tracer amounts of the complex were also administered intravesically to three patients with bladder cancer, who were then imaged by gamma scintigraphy.

RESULTS

The complex was immunoreactive (70% +/- 17%) and specific for MUC1 antigens. A peak corresponding to a protein of 150 kDa was observed on size exclusion chromatography, showing that the complex was homogeneous. Binding to bladder tumors was observed in an ex vivo model in which tumors were successfully imaged in four specimens. The mean tumor-to-normal tissue ratio in ex vivo bladders was 7:1. Tumor uptake after intravesical administration was confirmed in three patients with bladder cancer (mean tumor-to-normal tissue ratio, 4:1).

CONCLUSION

The C595 antibody was labeled with 188Re, providing a radioimmunoconjugate with high immunoreactivity and specificity. Its ability to localize in tumors both in an ex vivo model and after intravesical administration to patients has been shown. This approach will now be extended for the therapy of superficial bladder cancer.

Prospective study of morbidity after tonsillectomy in children

Post-operative morbidity was prospectively studied in 384 children after tonsillectomy or adenotonsillectomy, using visual analogue scores to record symptom levels, and questionnaires to monitor satisfaction scores from the children and their families. Assessments were performed between the 7th and 14th day post-operatively. Two hundred children were assessed before the introduction of a pre-admission programme which consisted of an instructional videotape session in the ward and an advice booklet. Department practice was also changed to provide a bottle of paracetamol on discharge routinely for each child. Following these changes in practice a further 184 children were assessed. The provision of relatively simple measures in the programme increased parental satisfaction rates (P<0.05) and reduced GP contact rates (35--17%, P<0.05) post-operatively. The actual levels of morbidity were unchanged despite the provision of analgesia.

Follicular development in vitro

There has been tremendous interest in recent years in the culture of oocytes and follicles. Although much of the research using follicle culture aims to increase understanding of the regulation of follicle development, an important goal has been to develop a method that will eventually allow maturation of human oocytes from the primordial follicle to the mature Graafian stage. We are still some way from this at present, although it has now been achieved in the mouse. In this article, we consider various methods of follicle culture for primordial, preantral, and antral follicles. In vitro development of primordial follicles has used primarily whole ovaries or ovarian fragments as a source of follicles. Culture of later stages of follicle development uses mainly isolated follicular units, either whole (with an intact basement membrane and, in some cases, attached thecal cells) or nonintact (oocyte-somatic cell complexes, which may or may not have remnants of basement membranes and/or thecal cells attached).

Combined risk factors contributing to cerebral venous thrombosis in a young woman

Cerebral venous thrombosis is a rare condition affecting predominantly adolescents or young adults. The presentation is often non-specific, and delay in diagnosis is common. The otolaryngologist may be consulted about the radiological findings of lateral sinus thrombosis and mastoid changes. The association of congenital thrombophilia with unusual presentations of venous thrombosis, especially in young individuals is now well documented. We present a case of lateral and sagittal sinus thrombosis complicated by cerebral venous infarction in a girl with protein C deficiency and masked mastoiditis. Unusual forms of venous thrombosis, including cerebral venous thrombosis may develop in association with a single risk factor for thrombosis, but additional risk factors should be sought especially when thrombosis presents in very young individuals. This case draws attention to the multi-causal nature of cerebral venous thrombosis in young adults, and highlights the issue of masked mastoiditis. A coordinated approach by otolaryngological and haematological teams is recommended in such cases.

Switching from Ventolin CFC to Ventolin HFA is well tolerated and effective in patients with asthma

BACKGROUND

Environmental imperatives to eliminate the use of chlorofluorocarbon (CFC) propellants in metered-dose inhalers have led to the development of metered-dose inhalers with the hydrofluoroalkane (HFA-134a) propellants.

OBJECTIVES

To evaluate the clinical effect of switching from Ventolin CFC to Ventolin HFA and to compare the efficacy and safety of Ventolin CFC, Ventolin HFA, and placebo in patients with asthma.

METHODS

Multicenter, double-blind, randomized safety and efficacy trial comparing regular use of Ventolin CFC versus Ventolin HFA versus placebo for 12 weeks in 313 patients with asthma aged 12 years and older who received Ventolin CFC during a 3-week run-in period.

RESULTS

Patients who were switched from Ventolin CFC to Ventolin HFA maintained pulmonary function and other measures of asthma control at levels comparable with run-in baseline. Serial pulmonary function testing demonstrated that both Ventolin treatments had significantly greater mean improvement in FEV1 over baseline than the placebo group at treatment day 1 and weeks 6 and 12 (P < .001). Both Ventolin groups had comparable pulmonary function at every visit. Predose FEV1 values were maintained or improved over time with all treatments. Treatments were well-tolerated. The adverse event profile for both Ventolin treatments was comparable with placebo. No clinically relevant effects on ECG, vital signs, or clinical laboratory tests were noted. Asthma exacerbation rates were 4% to 5% in the Ventolin groups and slightly higher (8%) in the placebo group.

CONCLUSIONS

Patients who were switched from Ventolin CFC to Ventolin HFA maintained comparable asthma control with a similar safety profile.

A clinical study of the Korotkoff phases of blood pressure in children

BACKGROUND

Five Korotkoff phases are described in adults, but there are no studies of the Korotkoff phase distribution in children. This study determines the presence and length of Korotkoff phases in children, providing data on the repeatability of these measurements, the relationship between the phases, and finally the relationship between the phases and heart rate, blood pressure and arm circumference.

METHODS

Seventy, 11-year-old children were studied. The Korotkoff sounds were recorded from the bell of a stethoscope to a MiniDisc system and each sound described twice on separate occasions as phase I, II, III or IV, with phase V meaning disappearance of the sound.

RESULTS

Phases I, II, III, IV and V were present in 97% (68/70), 61% (43/70), 51% (36/70), 88% (62/70) and 80% (56/70) respectively. When the recordings were blindly re-assessed there was no significant difference in the phase distribution of the sounds. All five phases were present in 40% (28/70). Phase III only occurred in the presence of phase II (P < 0.0001). There was no significant relationship between the presence of the different phases and heart rate or blood pressure. Arm circumference was significantly larger in children with phase V present (P < 0.02).

CONCLUSIONS

The Korotkoff sounds and phase distribution present in normal children is described. Korotkoff sounds were consistently allocated to the various Korotkoff phases. This study provides insights into the problems of accurate diastolic blood pressure measurement. Phase V was more likely to be present with increasing arm circumference, but the variation in the occurrence of phases II and III remains unexplained.

Distribution of FMR1 and FMR2 alleles in Javanese individuals with developmental disability and confirmation of a specific AGG-interruption pattern in Asian populations

The number of trinucleotide repeats in the 5' untranslated regions of the FMR1 and FMR2 genes was determined by PCR in 254 Fragile XA-negative Javanese male children with developmental disabilities. The distribution of FMR1 and FMR2 trinucleotide repeat alleles was found to be significantly different in the Indonesian population with developmental disability compared to that in developmentally disabled populations in North America and Europe (p & 0.021). Sequence analysis was performed on the trinucleotide repeat arrays of the 27 individuals with FMR1 alleles in the 'grey zone' (35-54 repeats). A repeat array structure of 9A9A6A9 was found in 16 unrelated individuals with 36 repeats, confirming earlier observations in intellectually normal Japanese. We propose that this FMR1 array pattern is specific for Asian populations and that Javanese and Japanese populations arose from a single progenitor population.

Effect of pre-slaughter overnight feed withdrawal on pig carcass and muscle quality

The effects of three feed withdrawal treatments (unfasted, 15 h overnight fast at the abattoir, 15 h overnight fast at the piggery) and three additional abattoir lairage times (0–1, 2–3 or 4–5 h) on pig carcass and non-carcass body component yields and on muscle quality characteristics were evaluated. Liveweight yield was lower (P < 0.05) for pigs fasted in the abattoir (by 17 g kg–1) and the piggery (by 22 g kg–1) than for unfasted pigs given a 2–5 h abattoir lairage. Of this decrease, 40–50% was attributed to a lower carcass yield, while the remainder was attributed to a decrease in yield of non-carcass components, especially the gastrointestinal tract. Feed withdrawal decreased (P < 0.05) the amount of distension of the intestinal tract, and increased (P < 0.05) the amount of carcass skin damage due to fighting. It had no effect (P > 0.05) on carcass lean yield, amount of shrink during the chilling process, yield of wholesale cuts, yields of dissected lean, fat and bone in the wholesale cuts, or moisture, fat and protein levels in the longissimus thoracis (LT) muscle. The overnight fast had little impact on LT muscle quality with the exception of slight darkening of the colour of muscles of pigs from which feed was withdrawn at the piggery. Feed withdrawal has the potential to reduce the problem of disposal of gut contents and the risk of carcass contamination as a result of nicking the gastrointestinal tract, and to slightly darken muscle tissue without affecting other meat quality traits. These benefits must be balanced against a decreased carcass yield and an increase in skin damage due to fighting. Key words: Feed restriction, fasting, gastrointestinal tract, gut fill, carcass yield, pork quality

Molecular and phylogenetic characterisation of Cryptosporidium from birds

Avian isolates of Cryptosporidium species from different geographic locations were sequenced at two loci, the 18S rRNA gene and the heat shock gene (HSP-70). Phylogenetic analysis of the sequence data provided support for the existence of a new avian species of Cryptosporidium infecting finches and a second species infecting a black duck. The identity of Cryptosporidium baileyi and Cryptosporidium meleagridis as valid species was confirmed. Also, C. baileyi was identified in a number of isolates from the brown quail extending the host range of this species.

Production and characterisation of a C595 antibody-99mTc conjugate for immunoscintigraphy of bladder cancer

Current radiological techniques for staging bladder cancer are inaccurate, especially in the identification of pelvic lymph node metastases. Immunoscintigraphy has the potential to offer improved staging for bladder cancer. The aim of this study was to label the anti-MUC1 monoclonal antibody C595 with 99mtechnetium (Tc), the most widely used diagnostic radionuclide, and assess the potential of the resultant conjugate for intravenous immunoscintigraphy of bladder cancer. A direct, reduction-mediated technique was used to label the antibody. The resultant conjugate was shown to be highly immunoreactive, stable and bound specifically to MUC1. The ability of the conjugate to bind to bladder tumours was demonstrated in an ex vivo model where the mean tumour:normal urothelial uptake was 5.7:1 and by intravesical administration in patients with bladder cancer where the mean tumour:normal urothelial uptake was 20.4:1. The ability of the conjugate to localise MUC1-expressing tumours was demonstrated in a nude mouse xenograft model. A conjugate of 99mTc-C595 has been produced and characterised, and it may be suitable for intravenous immunoscintigraphy, a potential novel staging tool for bladder cancer.

Balloon dacryocystoplasty study in the management of adult epiphora

PURPOSE

To determine the efficacy of dacryocystoplasty with balloon dilation in the treatment of acquired obstruction of the nasolacrimal system in adults.

METHODS

Balloon dacryocystoplasty was performed in 52 eyes of 42 patients under general anaesthetic. A Teflon-coated guidewire was introduced through the canaliculus and manipulated through the nasolacrimal system and out of the nasal aperture. A 4 mm wide 3 cm coronary angioplasty balloon catheter was threaded over the guidewire in a retrograde fashion and dilated at the site of obstruction.

RESULTS

There was complete obstruction in 30% of cases and partial obstruction in 70%. The most common site of obstruction was the nasolacrimal duct. The procedure was technically successful in 94% of cases. The overall re-obstruction rate was 29% within 1 year of the procedure. There was an anatomical failure rate of 17% for partial obstruction and 69% for complete obstruction within 1 year.

CONCLUSIONS

Balloon dacryocystoplasty has a high recurrence rate. There may be a limited role for this procedure in partial obstructions. Further refinements of the procedure are necessary before it can be offered as a comparable alternative to a standard surgical dacryocystorhinostomy.

Analogue VLSI for probabilistic networks and spike-time computation

The history and some of the methods of analogue neural VLSI are described. The strengths of analogue techniques are described, along with residual problems to be solved. The nature of hardware-friendly and hardware-appropriate algorithms is reviewed and suggestions are offered as to where analogue neural VLSI's future lies.