Results of posterior cervical foraminotomy for treatment of cervical spondylitic radiculopathy

We evaluated the results of posterior cervical foraminotomy for spondylitic radiculopathy using a questionnaire sent to all 77 patients who had undergone surgery between 1990 and 1995 at our institution. Sixty-two patients (40 male) returned their questionnaires, one of whom had undergone two procedures (dealt with as separate events). Sixty patients complained of pre-operative arm pain; of these 42 (70%) had complete or > 75% resolution of their pain, 14 (23%) had < 75% improvement in their pain and four (7%) had the same or worsened pain at the time of the questionnaire. Sixteen patients (27%) reported initial improvement in symptoms with subsequent deterioration. The mean patient satisfaction score using a linear analogue scale from 0 to 10 was 7.5. Main postoperative complaints were neck pain (22%), persisting motor deficit (6%) and persisting sensory deficit (9%). One patient suffered nerve root damage at surgery. For unilateral and, in some cases, multi-level degenerative disease causing cervical radiculopathy, posterior cervical foraminotomy is a useful technique with the advantage of avoiding fusion, immobilization and the long-term risk of instability.

A retrospective study of surgical and conservative treatment for spinal extradural abscess

The management of spinal extradural abscess (SEA), particularly the choice between surgical and conservative treatment, is controversial. We therefore undertook a retrospective study of patients admitted with this diagnosis: Details of presentation, treatment and outcome were obtained by review of inpatient notes and radiology. Twenty-five individuals with SEA aged 10-79 years were admitted between 1989 and 1995. Nine were treated non-operatively with antibiotics, of which three also underwent diagnostic CT-guided biopsy, and 16 underwent surgical drainage. There was no significant difference in the neurological features at presentation between the two groups. Two patients (8%) died; 11 (44%) patients remained the same and 12 (48%) improved following treatment. Four patients treated conservatively (44%) and seven treated surgically (43%) were capable of return to work or school, whilst a further seven patients (three treated conservatively and four treated surgically) were able to lead independent lives. No significant difference in outcome was demonstrated between patients treated non-operatively and those treated surgically. We conclude that certain carefully selected patients can be treated conservatively, but that surgery should remain the mainstay of management.

Transient deformation measurement with electronic speckle pattern interferometry by use of a holographic optical element for spatial phase stepping

We have used a computer-generated holographic optical element (HOE) with electronic speckle pattern interferometry to calculate the interference phase corresponding to the deformation of a test object from a single TV frame. The HOE is a modified crossed phase grating that introduces a known phase change between the +/-1 diffracted orders, without being translated. The progressive propagation of transient mechanical waves was measured with an rms precision of 2pi/30.

A study to investigate the ability of subjects with chronic lung diseases to activate the roadside Lion Alcolmeter SL-400

The Lion Alcolmeter SL-2 is widely used for road-side breath-testing by police in the UK. However, some individuals with lung diseases have difficulty in activating the device. This study describes an investigation that we have carried out on a new device called the Lion Alcolmeter SL-400 which has recently been introduced into use by police forces in the UK. The manufacturers state that the machine requires a minimum continuous expiratory flow rate of 25 litres per minute and a minimum expired volume of 1.5 litres, after which a breath sample is automatically taken and analysed. Our study was designed to investigate the ability of subjects with a variety of lung diseases to activate this device. The 40 adult subjects investigated consisted of 10 normal controls, 10 with asthma, 10 with chronic obstructive pulmonary disease and 10 with restrictive lung disease. After baseline lung function tests were performed, the subjects were then given alcohol to drink, the amount of which was based upon their body weight. After a gap of at least 20 minutes, the subjects were then asked to attempt up to three blows into the Alcolmeter. Our results showed that three asthmatic subjects, four with chronic obstructive pulmonary disease and two with restrictive lung disease, failed to successfully activate the device even after three attempts. All of the subjects who failed to activate the device had an expired breath volume of more than 1.5 litres, but seven out of these nine subjects had a Forced Expiratory Volume (FEV1) of less than 1.1 litres. In conclusion, this study has shown that some subjects with lung diseases may have difficulty in activating the SL-400 roadside alcolmeter device.

Developmental constraints on the mode of reproduction in the facultatively parthenogenetic cockroach Nauphoeta cinerea

Considerable work in evolutionary biology has focused on the question of why sex persists. Both advantages to sex and constraints limiting a return to asexual reproduction are hypothesized to maintain sex once it evolves. Developmental constraints would limit asexual reproduction from a sexual species if it were difficult for females to switch from making eggs that do not develop without fertilization to making zygotes that are capable of developing in the absence of fertilization. Nauphoeta cinerea is an ovoviviparous cockroach in which some females are capable of switching from a sexual mode of reproduction to an asexual mode when isolated from males. Yet, while facultative parthenogenesis can occur in individuals, few females make the switch. Thus, this cockroach provides an ideal system for examining the potential role of developmental constraints in maintaining sex. Here we compare the cytogenetics and embryonic development of sexual and parthenogenetic offspring in N. cinerea. We find that deviations from normal ploidy levels are associated with abnormal development. All viable N. cinerea embryos exhibit typically hemimetabolous insect embryogenesis. Although there is no variation among embryos in development within a sexually produced clutch, we see extreme variation in asexually derived clutches. These results suggest that developmental constraints limit the success of asexual reproduction in this facultatively parthenogenetic cockroach. Our data further suggest that the specific constraint occurs in the switch from a meiotic mode of reproduction requiring fertilization to diploid zygotes that develop in the absence of fertilization.

Transient deformation measurement with electronic speckle pattern interferometry and a high-speed camera

To the best of our knowledge, transient deformations have been measured in real time with microsecond temporal resolution for the first time with speckle pattern interferometry. The short exposure period and high framing rate of a high-speed camera at as many as 40,500 frames per second allow low-power continuous-wave laser illumination and fiber-optic beam delivery to be used. We have applied the technique to measure both harmonic vibration and transient deformation.

Posterior fossa meningiomas: surgical experience in 52 cases

BACKGROUND

Early reports of the surgical management of posterior cranial fossa meningiomas (PCFM) yielded poor results with high rates of mortality and morbidity. With the advent of modern neuroimaging and microsurgical techniques the results of surgery have improved markedly, but despite these advances removal of these lesions remains a challenge.

METHODS

The results of the surgical treatment of PCF meningiomas were examined with the aim to identify particular features associated with increased mortality and morbidity.

RESULTS

Of 713 patients with meningioma, 52 patients were identified with PCFM. Total macroscopic excision was achieved in 44 patients (84%). Postoperative complications occurred in 28 patients (54%) with permanent sequelae in 18 (35%). There were no mortalities in the immediate postoperative period. Follow-up ranged from 14 to 174 months (mean 42), tumour has recurred in 11 patients (21%) with a long-term mortality of 11%. At their latest follow-up 41 (79%) of patients achieved Glasgow outcome scores of 4 or 5.

CONCLUSIONS

Total excision of tumour should remain the goal of treatment in patients with PCFM. Despite the recent advances in preoperative planning and surgical techniques, the morbidity associated with surgery remains significant. Notwithstanding, the majority of patients achieve a good outcome with surgical treatment.

Skull base techniques for aneurysm occlusion

Aneurysms of the vertebrobasilar system carry relatively high operative mortality and morbidity due to their anatomical location. A variety of skull base techniques is described to improve access to these lesions and to reduce or abolish the need for retration on neurovascular structures. Surgical results are generally favorable and should encourage a more widespread application of these techniques in appropriate circumstances.

The value of screening for Down's syndrome in a socioeconomically deprived area with a high ethnic population

OBJECTIVE

To assess the utility of biochemical antenatal screening for Down's syndrome in a socioeconomically deprived area with a high proportion of Asian women from the Indian Subcontinent.

DESIGN

Audit of Down's syndrome biochemical screening service over a four-year period.

SETTING

Teaching hospital and community antenatal clinic in inner city Birmingham.

POPULATION

Women booked between October 1992 and December 1996.

METHODS

Blood for screening was collected between 14 and 21 weeks gestation, alpha-fetoprotein and intact human chorionic gonadotrophin were measured in serum and the risk of Down's syndrome was calculated.

MAIN OUTCOME MEASURES

Uptakes of screening and amniocentesis, screen positive rate, odds of being affected given a positive result, miscarriages associated with amniocentesis offered following a high risk result, detection rate, number of Down's cases prevented and a cost analysis. Outcome measures were compared between Asians and Caucasians.

RESULTS

Overall 11,974 women (71%) accepted serum screening. The screen positive rate was 8.3% in Asians and 5.0% in Caucasians. The uptake of amniocentesis in women following a high risk result was 54% overall (35% Asian, 67% Caucasian). Nineteen cases of Down's syndrome were identified, of which 13 occurred in women who opted for biochemical screening. The detection rate of the biochemical screening programme was 85% (11/13). Of these 11 cases, six (none of whom were Asian) elected to have an amniocentesis, of whom four thereafter had a termination.

CONCLUSION

In this study the public health benefits of screening for Down's syndrome in a socioeconomically deprived area with a high Asian population, were small.

Preoperative endovascular embolisation of a vertebral haemangioma

We describe the successful relief of compression of the spinal cord due to a vertebral haemangioma by transcatheter embolisation using cyanoacrylate compounds before operation, and provide a brief review of the literature.

Quantitative analysis of trabecular morphogenesis in the human costochondral junction during the postnatal period in normal subjects

BACKGROUND

Quantitative histomorphometric features of the bone growth plate in the human rib have been investigated in infants, ranging in age from 3-36 weeks (mean 18.6 weeks) to provide data currently not available.

METHODS

Measurements were taken in each histological zone of the growth plate. Data from 20 cases were pooled and parameters describing the characteristic features of trabecular bone calculated using morphometric formulae. The measurements were made from the resting zone of the cartilage to the secondary spongiosa, 3.78 mm from the starting point.

RESULTS

Cartilage volume fraction decreased from 78% in the resting zone to a bone volume fraction of between 20% and 30% in the secondary cancellous bone. Cartilage matrix surface increased rapidly in the cartilage and bone mineral surface declined in correspondence with the development of primary bone. The distance between chondrocyte lacunae was observed to decrease throughout the cartilage to a transverse septa thickness of 18 microns in the hypertrophic zone. A rapid increase in trabecular thickness to 128 microns was observed in the primary spongiosa, the secondary spongiosa ranging between 137 microns and 168 microns. Spacing, chondrocyte profile transverse diameter, increased to 30 microns in the hypertrophic zone, following which an increase in trabecular separation to 347 microns was observed in the primary spongiosa. The number of transverse intervals between individual chondrocyte lacunae was observed to increase in the cartilage to a maximum of 21.3 cartilaginous or mineralised septa per mm of growth plate length in the hypertrophic zone. Trabeculae in the metaphysis then decreased in number to approximately 1.5 trabeculae per mm in the secondary spongiosa.

CONCLUSIONS

These data thus provide new insight into the development of trabecular structure during growth and normal values for the comparison of tissue from skeletal dysplasias and growth disorders.

Contrast enhancement of electronic speckle pattern interferometry addition fringes

The electronic speckle pattern interferometer in the double-pulse addition mode can be used to measure physical parameters in unstable environmental conditions. Owing to additive optical noise, however, the fringe patterns obtained have poor contrast. Some methods that use subtraction of addition double-pulsed fringe patterns improve fringe visibility but impose a limitation in measurement time ranges. To increase this range, to be limited by only the pulse separation, the contrast enhancement of double-pulsed addition-fringe patterns with a spatial filter based on local-standard-deviation measurements is investigated. Computer simulations and experimental results are presented.

Study of transient deformations with pulsed TV holography: application to crack detection

We report the measurement of reproducible transient deformations with single-pulsed-subtraction and double-pulsed-addition TV holography with both in-plane and out-of-plane optical configurations. An original synchronization system (controlling mechanical excitation of the object, firing the laser pulses, and image acquisition) used to obtain the subtraction and the addition correlation fringes is described. Experimental results are presented for the propagation of mechanical shock waves in a cantilever specimen and their subsequent diffraction by a crack in the specimen. These preliminary results show that the technique may be used for crack detection.

Ambulatory care growth: implications for academic organizations

This article discusses the implications of the dramatic growth of outpatient activity in academic health care organizations, and, more broadly, in all forms of joint physician-hospital outpatient care. The authors describe several economic, operational, and regulatory factors that influence the success of ambulatory care expansion in the academic environment. A case study of the Metropolitan New York Medicaid managed care environment illustrates the impact of these factors and highlights the specific challenges confronting teaching hospitals and physicians. The attributes of ambulatory care providers that have successfully addressed these challenges are also discussed. Finally, the benefits of the model ambulatory practice structure, employed at a number of teaching institutions across the country, are explored.

Antimicrobial activity of cecropins

The lytic peptides, cecropins, were originally isolated from the haemolymph of the giant silk moth, Hyalophora cecropia and possess antibacterial and anticancer activity in vitro. This study investigated the antimicrobial activity of these peptides against human pathogens using standardised assay techniques, and the activity of cecropin B on outer and inner bacterial membranes. From a panel of 15 organisms, Gram-negative bacteria were generally more sensitive to cecropins than Gram-positive organisms, especially the lipopolysaccharide defective mutant, Escherichia coli BUE55. Cecropins B and P1 shared similar MIC values whereas Shiva-1, a cecropin B analogue, was less active. Through combination studies with hydrophobic antibiotics and electron microscopy, cecropin B was shown to disrupt the bacterial outer membrane. Protoplasts of Staphylococcus aureus and Staphylococcus epidermidis were resistant to cecropin B, suggesting that the cytoplasmic membranes of Gram-positive organisms were inherently more resistant to the peptide.

Enzyme replacement therapy in a feline model of Maroteaux-Lamy syndrome

We report studies that suggest enzyme replacement therapy will result in a significant reduction in disease progression and tissue pathology in patients with Maroteaux-Lamy syndrome (Mucopolysaccharidosis type VI, MPS VI). A feline model for MPS VI was used to evaluate tissue distribution and clinical efficacy of three forms of recombinant human N-acetylgalactosamine-4-sulfatase (rh4S, EC 3.1.6.1). Intravenously administered rh4S was rapidly cleared from circulation. The majority of rh4S was distributed to liver, but was also detected in most other tissues. Tissue half-life was approximately 2-4 d. Three MPS VI cats given regular intravenous infusions of rh4S for up to 20 mo showed variable reduction of storage vacuoles in Kupffer cells and connective tissues, however cartilage chondrocytes remained vacuolated. Vertebral bone mineral volume was improved in two MPS VI cats in which therapy was initiated before skeletal maturity, and increased bone volume appeared to correlate with earlier age of onset of therapy. One cat showed greater mobility in response to therapy.

Extraction of the synthetic lytic peptide, cecropin B, from biological fluid and analysis using reversed-phase high-performance liquid chromatography

The lytic peptide cecropin B, originally isolated from the giant silk moth Hyalophora cecropia, has been found to possess antibacterial and cell lysis properties in vitro and some anticancer activity in vivo. An HPLC method was developed to study synthetic cecropin B concentrations in biological fluids. Cecropin B was recovered from culture medium by solid-phase extraction (40.0 +/- 2.4%), whereas in plasma it was highly protein-bound. The peptide was dissociated from proteins by citric acid and recovered by ultrafiltration (64.6 +/- 5.9%) and was unstable in plasma (half-life, 0.57 +/- 0.11 h). These analytical methods will facilitate future in vivo pharmacokinetic studies.

Genetic aspects of communication during male-male competition in the Madagascar hissing cockroach: honest signalling of size

Male Madagascar hissing cockroaches, Gromphadorhina portentosa, engage in agonistic contests with other males and produce audible sounds or 'hisses' during these interactions. Hisses are used to maintain, rather than to establish, social relationships among males. The agonistic hisses of males are variable and could be used as signals to communicate size or competitive ability of an individual. In this study we examined how size influences male-male competition, as well as the genetic variation and covariation of male body size and components of the agonistic hiss. We found that male size affected the outcome of agonistic interactions between pairs of males: a male that dominated in a pair was significantly larger than the male that was subordinate. However, we found no differences in the hisses produced by dominant and subordinate males after controlling for male weight. We estimated heritabilities, evolvability and genetic correlations for male size and characteristics of the hiss from a full-sib analysis of brothers. The patterns of heritabilities and evolvabilities were very similar. The heritabilities of both male weight and duration of the hiss were significantly greater than zero. There was a significant positive genetic correlation between duration of the agonistic hiss and male weight, and a significant negative genetic correlation between hiss duration and the beginning dominant frequency. There was also a positive phenotypic correlation and a negative environmental correlation between male weight and hiss duration. Thus, hiss duration can signal the present influence of the environment on male size, whereas information from hiss duration and beginning dominant frequency can signal the male's ability to transmit genetic influence for size.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.

Inositol 1,2,3-trisphosphate and inositol 1,2- and/or 2,3-bisphosphate are normal constituents of mammalian cells

1. An inositol trisphosphate (InsP3) distinct from Ins(1,4,5)P3 and Ins(1,3,4)P3, which we previously observed in myeloid and lymphoid cells [French, Bunce, Stephens, Lord, McConnell, Brown, Creba and Michell (1991) Proc R. Soc. London B 245, 193-201; Bunce, French, Allen, Mountford, Moore, Greaves, Michell and Brown (1993) Biochem. J. 289, 667-673], is present in WRK1 rat mammary tumour cells and pancreatic endocrine beta-cells. 2. It has been identified as Ins(1,2,3)P3 by a combination of oxidation to ribitol, a structurally diagnostic polyol, and ammoniacal hydrolysis to identified inositol monophosphates. 3. Ins(1,2,3)P3 concentration in HL60 cells changed little during stimulation by ATP or fMetLeuPhe or during neutrophilic or monocytic differentiation, and Ins(1,2,3)P3 was unresponsive to vasopressin in WRK1 cells. 4. Ins(1,2,3)P3 was usually more abundant than Ins(1,4,5)P3, often being present at concentrations between approximately 1 microM and approximately 10 microM. 5. HL60, WRK-1 and lymphoid cells also contain Ins(1,2)P2 or Ins(2,3)P2, or a mixture of these two enantiomers, as a major InsP2 species. 6. Ins(1,2,3)P3 and Ins(1,2)P2/Ins(2,3)P2 are readily detected in cells labelled for long periods, but not in acutely labelled cells. This behaviour resembles that of InsP6, the most abundant cellular inositol polyphosphate that includes the 1,2,3-trisphosphate motif, which also achieves isotopic equilibrium with inositol only slowly. 7. Ins(1,2,3)P3 is the major InsP3 that accumulates during metabolism of InsP6 by WRK-1 cell homogenates. 8. Possible metabolic relationships between Ins(1,2,3)P3, Ins(1,2)P2/Ins(2,3)P2 and other inositol polyphosphates in cells, and a possible role for Ins(1,2,3)P3 in cellular iron handling, are considered.

Coronary heart disease risk factors in a rural and urban Orange Free State black population

OBJECTIVE

To determine and compare the prevalence of ischaemic heart disease (IHD) risk factors in a rural and an urban black population.

DESIGN

A survey to determine the prevalence of hypertension, diabetes mellitus, smoking, obesity, central obesity and dyslipidaemia in black subjects 25 years and older.

SETTING

The indigenous black populations of QwaQwa and Mangaung.

PARTICIPANTS

A random sample of 950 households was selected from each area. From each household an unrelated male and/or female subject was selected in a standardised way. From QwaQwa 853 subjects (279 men and 574 women) and from Mangaung 758 subjects (290 men and 468 women) participated in the study. The response rate was 68% and 62% respectively for QwaQwa and Mangaung.

MAIN OUTCOME MEASURES

Few urban-rural differences in the prevalence of IHD risk factors were found in this study. A low prevalence of clustering of major IHD risk factors was noted.

RESULTS

The age- and sex-adjusted prevalences of hypertension were 29% in QwaQwa and 30.3% in Mangaung. Diabetes was present in 4.8% of the QwaQwa sample and 6% of the Mangaung sample. The prevalence of heavy smoking in the Mangaung sample was almost double that of the QwaQwa sample and mostly confined to men. High-risk hypercholesterolaemia was present in 12.5% of QwaQwa and 6% of Mangaung men in the 25-34-year age group. The corresponding figures for moderate-risk hypercholesterolaemia were 34% and 44.8% and both levels of risk declined with increasing age. The mean body mass index of women in both samples exceeded 25 kg/m2.

CONCLUSION

All the elements for a potential epidemic of atherosclerotic cardiovascular disease are present in the study populations. The similarity of findings in the two samples may be indicative of the advanced stage of urbanisation and westernisation of the rural group. It is alarming that subjects in the younger age groups tended to have the highest prevalences of moderate and even high-risk hypercholesterolaemia.

Outcome after repeat lumbar microdiscectomy

One of the standard treatments for herniation of lumbosacral disc material has become the microdiscectomy. Although multiple studies have assessed the outcome of microdiscectomy, only a few studies have evaluated the outcome of those patients who have undergone a second microdiscectomy at the same location as the original one. The purpose of this study was to review 55 patients who, over a 4-year period, underwent a second microdiscectomy at the same location as their original operation and to evaluate those factors associated with improved outcomes. The results showed the overall outcome to include 86% with complete or partial relief of all pain symptoms; 88% with complete or partial relief of sciatica; 85% with complete or partial relief of back pain; 100% returning to work in an average of 7 weeks; and 89% were glad they had the second operation. Those factors without predictive value included age, sex, weight, height, level of operation, side of operation, surgeon at the first or second operation (e.g. consultant or junior staff), length of the first operation ( < or = 60 min or > 60 min) and duration of symptoms before the first operation. The key features centred on preoperative job status, the interval between recurrence of symptoms and the second operation, and the duration of the second operation ( < or = 90 min).(ABSTRACT TRUNCATED AT 250 WORDS)

Phase extraction from electronic speckle pattern interferometry addition fringes

Addition fringes are obtained in real time from electronic speckle pattern interferometry (ESPI) by use of a twin-pulsed laser when two pulses are fired during a single field of a CCD camera. This enables object deformations to be studied in harsh environmental conditions. However, the fringe patterns have poor visibility because optical noise is additive. To our knowledge automatic phase extraction from addition fringes has not previously been achieved: Low-pass filtering to suppress random speckle noise also eliminates the fringes because of their low visibility. Two phase-stepping algorithms that calculate phase from ESPI fringes without the need for a preprocessing filter are presented. In the first ESPI subtraction fringes are considered, for which an improvement in accuracy is seen, and in the second ESPI addition fringes are considered, which, we believe, has enabled the phase to be extracted for the first time. The algorithms are demonstrated with theoretical data and with experimental ESPI fringepatterns recorded with a cw laser. As presented, they form the first step toward a procedure that can beused with twin-pulsed ESPI.