Calcium requests in a primary care; An observational audit of biochemical requests and frequency of abnormal results

BACKGROUND/AIMS

This aim of this audit was to assess the extent of serum calcium testing and the frequency of hypercalcaemia in the primary care setting. We also assessed the appropriateness of subsequent investigations with repeat serum calcium and PTH testing if hypercalcaemia was identified.

METHODS

All laboratory requests for adjusted calcium and PTH samples sent from primary care in Glasgow were analysed over a 12 month period. This covered approximately 125 GP practices and a patient population of over 590,000.

RESULTS

There were 78,845 requests for adjusted calcium and 2053 PTH requests from 62,745 patients aged 16-105 years (median age 57, IQ range 30 years). Of these requests 1423 (2.3%) of patients had biochemical evidence of hypercalcaemia (adjusted calcium ≥ 2.61 mmol/L). Of the 1423 patients with hypercalcaemia, 368 patients (45.8%) had a single raised calcium level that was within the normal range on repeat testing. Of the 400 patients with persistent hypercalcaemia on 2 or more samples, 210 (52.5%) had a PTH measured. Eight patients had a PTH < 2.0 pmol/L, whilst 202 (96.1%) had a PTH ≥ 2.0 pmol/L (range 2.1-106.1 pmol/L).

CONCLUSIONS

Serum calcium was checked in 10.6% of the population per year within primary care. In the 2.4% with a raised calcium on initial testing, approximately half (45.8%) will normalise on repeat testing. Of those who remained persistently hypercalcaemic, only half (52.5%) had a PTH measured and the majority (96.1%) were in keeping with primary hyperparathyroidism being the most common cause of hypercalcaemia.

Quantitative Determination of Paralytic Shellfish Poisoning Toxins in Shellfish Using Prechromatographic Oxidation and Liquid Chromatography with Fluorescence Detection: Collaborative Study

A collaborative study was conducted for the determination of paralytic shellfish poisoning (PSP) toxins in shellfish. The method used liquid chromatography with fluorescence detection after prechromatographic oxidation of the toxins with hydrogen peroxide and periodate. The PSP toxins studied were saxitoxin (STX), neosaxitoxin (NEO), gonyautoxins 2 and 3 (GTX2,3; together), gonyautoxins 1 and 4 (GTX1,4; together), decarbamoyl saxitoxin (dcSTX), B-1 (GTX5), C-1 and C-2 (C1,2; together), and C-3 and C-4 (C3,4; together). B-2 (GTX6) toxin was also included, but for qualitative identification only. Mussels, both blank and naturally contaminated, were mixed and homogenized to provide a variety of PSP toxin mixtures and concentration levels. The same procedure was followed with clams, oysters, and scallops. Twenty-one test samples in total were sent to 21 collaborators who agreed to participate in the study. Results were obtained from 18 laboratories representing 14 different countries. It is recommended that the method be adopted First Action by AOAC INTERNATIONAL.

The colonisation of the glenohumeral joint by Propionibacterium acnes is not associated with frozen shoulder but is more likely to occur after an injection into the joint

AIMS

Our aim was to investigate the prevalence of Propionibacterium (P.) acnes in the subcutaneous fat and capsule of patients undergoing shoulder surgery for frozen shoulder or instability.

PATIENTS AND METHODS

A total of 46 patients undergoing either an arthroscopic capsular release or stabilisation had biopsies taken from the subcutaneous fat and capsule of the shoulder at the time of surgery. These samples were sent for culture in enrichment, and also for Nucleic Acid Amplification testing. The prevalence of P. acnes and other microbes was recorded. Fisher's exact test of binary variables was used to calculate the association with significance set at p < 0.05. Assessment of influence of independent variables including a pre-operative glenohumeral injection, fat colonisation and gender, was undertaken using binary linear regression.

RESULTS

A total of 25 patients (53%) had P. acnes in one or more tissue samples and 35 (74%) had other bacterial species. The same microbe was found in the subcutaneous fat and the capsule in 13 patients (28%). There was no statistically significant association between the surgical pathology and capsular colonisation with P. acnes (p = 0.18) or mixed identified bacterial species (p = 0.77). Male gender was significantly associated with an increased capsular colonisation of P. acnes (odds ratio (OR) 12.38, 95% confidence interval (CI) 1.43 to 106.77, p = 0.02). A pre-operative glenohumeral injection was significantly associated with capsular P. acnes colonisation (OR 5.63, 95% CI 1.07 to 29.61, p = 0.04. Positive fat colonisation with P. acnes was significantly associated with capsular P. acnes (OR 363, 95% CI 20.90 to 6304.19, p < 0.01). Regression models pseudo R² found fat colonisation with P. acnes to explain 70% of the variance of the model. Patients who had a pre-operative glenohumeral injection who were found intra-operatively to have fat colonisation with P. acnes had a statistically significant association with colonisation of their capsule with P. acnes (OR 165, 95% CI 13.51 to 2015.24, p < 0.01).

CONCLUSION

These results show a statistically significant association between subcutaneous skin P. acnes culture and P. acnes capsular culture, especially when the patient has undergone a previous injection. The results refute the hypothesis that P. acnes causes frozen shoulder. Cite this article: Bone Joint J 2017;99-B:1067-72.

Primary Hypoparathyroidism Resistant to Conventional Therapy

A 28 year old man with primary hypoparathyroidism failed to respond to treatment with calcium and vitamin D analogues. Despite extensive investigation no reason for this was found and he is now successfully treated with teriparatide (synthetic human PTH)

Using WHO-FRAX to describe fracture risk: experience in primary care

Ideally those at highest risk of fracture should be identified prior to fracture occurrence to reduce mortality, morbidity and costs. Case-finding strategies for those at high risk of first fracture or systematic case-finding strategies following fracture are recommended in the UK, rather than population-based screening to identify individuals at high fracture risk. General practices in the UK hold relevant data on individuals beyond fracture history that could allow identification of a wider group of patients at highest risk of fracture. The aim of the paper is to evaluate the feasibility of applying the WHO-FRAX fracture risk calculator to general practice populations using existing recorded data. A cross-sectional study of 2467 women aged 50 years and older (mean 66.2 years, standard deviation = 11.3) registered with two Scottish General Practices with low deprivation (one semi-rural, one urban) was undertaken. Patient data were extracted from the two general practices' patient information databases and the WHO-FRAX calculator was applied to these data. WHO-FRAX calculation was possible on 1872 patients. Of these, 687 patients were found to have a high fracture risk (risk of major facture ≥15% and or risk of hip fracture ≥3% - 37% of the WHO-FRAX assessed cohort) and should be considered for follow-up. In conclusion, use of the WHO-FRAX calculator using general practice-held data is feasible and can help to identify a patient group at higher fracture risk. Further evaluation and treatments can then be targeted at this group.

Impact of treatments for postmenopausal osteoporosis (bisphosphonates, parathyroid hormone, strontium ranelate, and denosumab) on bone quality: a systematic review

The objective of this systematic review was to examine the influence of treatments for postmenopausal osteoporosis (parathyroid hormone [PTH], bisphosphonates, strontium ranelate, and denosumab) on bone quality and discuss the clinical implications. Most bone-quality data for PTH is from teriparatide. Teriparatide results in a rapid increase in bone-formation markers, followed by increases in bone-resorption markers, opening an "anabolic window," a period of time when PTH is maximally anabolic. Teriparatide reverses the structural damage seen in osteoporosis and restores the structure of trabecular bone. It has a positive effect on cortical bone, and any early increases in cortical porosity appear to be offset by increases in cortical thickness and diameter. Bisphosphonates are antiresorptive agents which reduce bone turnover, improve trabecular microarchitecture, and mineralization. Concerns have been raised that the prolonged antiresorptive action of bisphosphonates may lead to failure to repair microdamage, resulting in microcracks and atypical fragility. Strontium ranelate is thought to have a mixed mode of action, increasing bone formation and decreasing bone resorption. Strontium ranelate improves cortical thickness, trabecular number, and connectivity, with no change in cortical porosity. Denosumab exerts rapid, marked, and sustained effects on bone resorption, resulting in falls in the markers of bone turnover. Evidence from bone-quality studies suggests that treatment-naive women, aged 60-65 years, with very low BMD T scores may benefit from PTH as primary therapy to improve bone substrate and build bone. Post-PTH treatment with bisphosphonates will maintain improvements in bone quality and reduce the risk of fracture.

A sensitive and reliable reverse transcriptase PCR-enzyme-linked immunosorbent assay for the detection of human pathogenic viruses in bivalve molluscs

A colorimetric method, reverse transcriptase PCR with an enzyme-linked immunosorbent assay (RT-PCR-ELISA) was evaluated for ease of use, reliability, and sensitivity when detecting known human pathogenic virus present in shellfish, using a traditional polyethylene precipitation or immunocapture virus concentration method. The newly developed ELISA method could successfully detect enteroviruses and noroviruses in artificially and naturally contaminated shellfish. Overall, ELISA was shown to be a robust and sensitive method, which had a detection limit of 10 to 100 50% tissue culture infective dose enterovirus per gram of Crassostrea gigas (Pacific oyster) digestive gland and whole Mytilus edulis (common blue mussel). The technique was easily established in a new laboratory and required no specialized equipment. The method had a high sample throughput capable of screening 96 samples per run, making the technique extremely time efficient. RT-PCR-ELISA is a safe, quick, reliable technique, which has the potential for use as a standard virus detection method.

The prevalence of vertebral fracture amongst patients presenting with non-vertebral fractures

INTRODUCTION

Despite vertebral fracture being a significant risk factor for further fracture, vertebral fractures are often unrecognised. A study was therefore conducted to determine the proportion of patients presenting with a non-vertebral fracture who also have an unrecognised vertebral fracture.

METHODS

Prospective study of patients presenting with a non-vertebral fracture in South Glasgow who underwent DXA evaluation with vertebral morphometry (MXA) from DV5/6 to LV4/5. Vertebral deformities (consistent with fracture) were identified by direct visualisation using the Genant semi-quantitative grading scale.

RESULTS

Data were available for 337 patients presenting with low trauma non-vertebral fracture; 261 were female. Of all patients, 10.4% were aged 50-64 years, 53.2% were aged 65-74 years and 36.2% were aged 75 years or over. According to WHO definitions, 35.0% of patients had normal lumbar spine BMD (T-score -1 or above), 37.4% were osteopenic (T-score -1.1 to -2.4) and 27.6% osteoporotic (T-score -2.5 or lower). Humerus (n=103, 31%), radius-ulna (n=90, 27%) and hand/foot (n=53, 16%) were the most common fractures. For 72% of patients (n=241) the presenting fracture was the first low trauma fracture to come to clinical attention. The overall prevalence of vertebral deformity established by MXA was 25% (n=83); 45% (n=37) of patients with vertebral deformity had deformities of more than one vertebra. Of the patients with vertebral deformity and readable scans for grading, 72.5% (58/80) had deformities of grade 2 or 3. Patients presenting with hip fracture, or spine T-score

CONCLUSIONS

Our results support the recommendation to perform vertebral morphometry in patients who are referred for DXA after experiencing a non-vertebral fracture. Treatment decisions will then better reflect any given patient's future absolute fracture risk. The 'Number Needed to Screen' if vertebral morphometry is used in this way would be seven to identify one patient with vertebral deformity, and 14 to identify one patient with two or more vertebral deformities. Although carrying out MXA will increase radiation exposure for the patient, this increased exposure is significantly less than would be obtained if X-rays of the dorso-lumbar spine were obtained.

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Key Words

• low trauma fracture
• number needed to screen
• osteoporosis
• vertebral fracture
• vertebral morphometry

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MESH Headings

• Absorptiometry, Photon/methods
• Age Factors
• Aged
• Body Mass Index
• Female
• Fractures, Bone/diagnosis
• Fractures, Bone/epidemiology
• Humans
• Lumbar Vertebrae/abnormalities
• Lumbar Vertebrae/injuries
• Male
• Middle Aged
• Osteoporosis/diagnosis
• Osteoporosis/epidemiology
• Prevalence
• Prospective Studies
• Recurrence
• Risk Factors
• Scotland/epidemiology
• Spinal Fractures/diagnosis
• Spinal Fractures/epidemiology
• Thoracic Vertebrae/abnormalities
• Thoracic Vertebrae/injuries

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Affiliation(s)

S J Gallacher Medical Unit, Southern General Hospital, 1345 Govan Road, Glasgow, G51 4TF, UK.
A P Gallagher
C McQuillian
P J Mitchell
T Dixon

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Peri-prosthetic bone mineral density after total knee arthroplasty

We compared peri-prosthetic bone mineral density between identical cemented and cementless LCS rotating platform total knee arthroplasties. Two matched cohorts had dual energy x-ray absorptiometry scans two years post-operatively using a modified validated densitometric analysis protocol, to assess peri-prosthetic bone mineral density. The knee that was not operated on was also scanned to enable the calculation of a relative bone mineral density difference. Oxford Knee and American Knee Society scores were comparable in the two cohorts.

Statistical analysis revealed no significant difference in absolute, or relative peri-prosthetic bone mineral density with respect to the method of fixation. However, the femoral peri-prosthetic bone mineral density and relative bone mineral density difference were significantly decreased, irrespective of the method of fixation, particularly in the anterior distal portion of the femur, with a mean reduction in relative bone mineral density difference of 27%.

There was no difference in clinical outcome between the cemented and cementless LCS total knee arthroplasty. However, both produce stress-shielding around the femoral implants. This leads us to question the use of more expensive cementless total knee components.

A reliable RT-PCR–ELISA method for the detection of infectious pancreatic necrosis virus (IPNV) in farmed rainbow trout

A new method, termed RT-PCR-ELISA, was evaluated for ease of use, reliability and sensitivity when detecting infectious pancreatic necrosis virus (IPNV) present in trout kidney tissue. The method had comparable sensitivity to existing PCR assays and could successfully detect 1.5 x 10(4) pfu IPNV in artificially contaminated trout kidney samples. The technique was easily established in a new laboratory and required no specialised equipment. The method had a high sample throughput capable of screening 96 samples per run, making the technique extremely time efficient. The RT-PCR-ELISA is a safe, quick, reliable technique, which has the potential for use as a standard virus detection method.

An overview of the prevalence of 25-hydroxy-vitamin D inadequacy amongst elderly patients with or without fragility fracture in the United Kingdom

BACKGROUND

Many studies have investigated the prevalence of 25-hydroxy-vitamin D inadequacy throughout the world and found a high prevalence of 25-hydroxy-vitamin D inadequacy in older patients, particularly those with fragility fracture.

SCOPE

To review the findings from vitamin D audits from six units across the UK and compare with previously published data from around the world. Results from four units have been previously published (Belfast, Glasgow, London and Medway) and this paper presents new data from Southampton and Carshalton, and further sub-analysis of the data from Medway.

FINDINGS

Three audits of patients attending metabolic bone clinics (Carshalton, Medway and Southampton) identified 954 patients, of which overall 49% had a prior fragility fracture. Mean 25-hydroxy-vitamin D levels ranged from 47.7 nmol/L to 62.4 nmol/L. Of these patients 72.9-88.9% had a 25-hydroxy-vitamin D level < 80 nmol/L, 68.8-83.3% < 70 nmol/L and 37.5-59.1% < 50 nmol/L. The mean age of patients ranged from 60.0 to 67.5 years. Sub-analysis of the data by fracture status revealed that patients with fracture had lower mean levels of 25-hydroxy-vitamin D compared with patients without fracture. This was statistically significant in the sub-analysis of the Medway data (45.3 nmol/L versus 49.9 nmol/L, p < 0.005). Three audits identified 330 patients with fragility fracture. Audits from Glasgow and Belfast specifically identified patients with fragility fracture. A subgroup of patients with fracture aged over 50 years from the Medway audit was also included in this group. Mean levels of 25-hydroxy-vitamin D ranged from 40.0 nmol/L to 52.3 nmol/L. 83.7-96.4% of patients had a 25-hydroxy-vitamin D level < 80 nmol/L, 73.3-89.7% < 70 nmol/L and 55.8-73.2% < 50 nmol/L. The mean age of patients ranged from 65.3 to 68.6 years. The audits carried out in Belfast and Medway were also divided by supplementation status. Mean 25-hydroxy-vitamin D levels were 48.1 nmol/L in Belfast and 40.5 nmol/L in Medway in the patients not receiving supplements and 53.8 nmol/L and 59.9 nmol/L, respectively in the patients receiving supplements. The difference was statistically significant in the Medway audit (p < 0.0001), but not in the smaller Belfast audit (p = 0.216). As would be expected, the prevalence of 25-hydroxy-vitamin D inadequacy was higher in the patients not receiving supplements, for example at the 70 nmol/L threshold: 82.6% versus 67.1% in Belfast and 89.6% versus 72.7% in Medway. Three audits specifically identified 694 patients with hip fracture (Belfast, Glasgow and London). Mean levels of 25-hydroxy-vitamin D ranged from 24.7 nmol/L to 36.1 nmol/L. Of these patients 90.7-99.0% had a 25-hydroxy-vitamin D level < 80 nmol/L, 88.4-98.0% < 70 nmol/L and 81.6-92.7% < 50 nmol/L. The mean age of patients ranged from 73.4 to 80.5 years.

CONCLUSION

Inadequate 25-hydroxy-vitamin D levels are extremely common in the elderly and particularly so in patients with fragility fracture - specifically in those with hip fracture. Although the differing audit specifications and assay techniques used make direct comparisons difficult, the data do provide a snapshot of 25-hydroxy-vitamin D status across the UK and are consistent with those previously observed elsewhere in Europe and the rest of the world.

Osteoporosis risk assessment and treatment intervention after hip or shoulder fracture. A comparison of two centres in the United Kingdom

This study compares the investigation of and treatment for osteoporosis in two groups of fracture patients at two orthopaedic centres in the UK. One centre had a formal fracture liaison service (FLS) responsible for screening fracture patients for osteoporosis. The other centre relied upon individual clinicians to initiate investigation or treatment for osteoporosis in patients following fracture. Patients who had been treated in either centre for a proximal humeral or hip fracture during a 6-month period were followed up 6 months later to identify how many had received screening or treatment for osteoporosis. Information was retrieved from a prospectively compiled database or by postal questionnaire. The study revealed that in the centre with an FLS 85% of patients with a proximal humeral fracture and 20% with a hip fracture had been offered a dual-energy X-ray absorptiometry (DEXA) scan. Approximately 50% and 85%, respectively, were receiving treatment for osteoporosis 6 months following their fracture. This compared with DEXA being offered to only 6% and 9.7% of humeral and hip fracture patients, respectively, and 20% (hip) and 27% (proximal humerus) receiving osteoporosis treatment in the other centre. The presence of an FLS resulted in a considerably higher proportion of patients receiving investigation and treatment for osteoporosis following a hip or proximal humeral fracture.

Prevalence of vitamin D inadequacy in Scottish adults with non-vertebral fragility fractures

BACKGROUND

It is well established that vitamin D levels are sub-optimal in the elderly and that adults with fragility fracture are more likely to have serum vitamin D levels either lower than those of control patients of similar age, or below the normal range.

OBJECTIVES

To investigate the prevalence of vitamin D inadequacy in an elderly population presenting to the South Glasgow Fracture Liaison Service with non-vertebral fragility fractures in order to assess the extent of the problem.

RESEARCH DESIGN AND METHODS

The retrospective arm of this study used data from an established database to identify patients aged over 50 years admitted to South Glasgow University Hospitals over the previous 4 years with hip fracture. The prospective arm identified the first 50 patients aged over 50 presenting with a clinical non-vertebral fragility fracture with osteoporosis as measured by axial spine and/or hip DEXA (T-score < -2.5) after November 2004.

RESULTS

In the retrospective arm, 626 patients were identified from the database: mean age 80.5 years; 94% were aged over 60 and 74% were aged over 75. Data analysis was limited to 548 patients aged over 60 years with vitamin D recordings and not receiving supplementation with calcium and vitamin D. The mean vitamin D level was 24.7 nmol/L (9.9 ng/ml) SD = 17, however, it is likely that the true mean is lower since in approximately 25% of cases vitamin D levels were reported as < 15 nmol/L (effectively unrecordable). These were transcribed as 15 nmol/L in order to permit a numerical value to be calculated. In the absence of an agreement on what should constitute a diagnostic serum level of vitamin D inadequacy, a number of thresholds were considered--97.8% had vitamin D levels below 70 nmol/L and 91.6% had vitamin D levels below 50 nmol/L. There were no significant differences by patient sex, age or season of presentation. The mean age of patients in the prospective arm was 65.8 years (range 50.6-83.8), 72% were aged over 60 and 16% were aged over 75. The mean vitamin D level was 44.1 nmol/L (18.4 ng/ml) SD = 25.3; 82% had vitamin D levels below 70 nmol/L and 72% had vitamin D levels below 50 nmol/L. Although numbers were too small to justify extensive subgroup analyses, the mean vitamin D level in the 13 patients with hip fracture (34.5 nmol/L) was lower than in the 37 with non-hip fractures (48.2 nmol/L).

CONCLUSIONS

This study confirms almost universal vitamin D inadequacy among 548 elderly patients admitted to hospital with hip fracture, regardless of whether a threshold of 50 nmol/L or 70 nmol/L was used. However, among a prospective subset of 50 patients with clinical fragility fractures, especially those with non-hip fractures, the prevalence of inadequacy was substantially lower. It may be that vitamin D represents a correctable risk factor for fragility fracture in the elderly, possibly specifically for the hip.

Determination and confirmation of the amnesic shellfish poisoning toxin, domoic acid, in shellfish from Scotland by liquid chromatography and mass spectrometry

During 1998 and early 1999, shellfish samples from sites in Scotland were found to contain the amnesic shellfish poisoning toxin, domoic acid (DA). Two different techniques, liquid chromatography (LC) with UV diode-array detection and LC with mass spectrometric (MS) detection, were used to detect and confirm DA in shellfish extracts. The LC/UV method was validated for routine monitoring by recovery experiments on spiked mussel and scallop tissues with a certified mussel tissue used as reference material. Crude extracts of selected samples as well as extracts cleaned with strong anion exchange (SAX) were analyzed by both LC/UV and LC/MS. Good correlation (linear regression r2 = 0.996, slope = 0.93) between the 2 methods was found for cleaned extracts. Analyses of crude extracts by LC/UV produced false-positive results in 2 crab samples, whereas LC/MS analyses gave accurate results. It was concluded that LC/UV is a valid approach for routine monitoring of DA in shellfish when cleanup is performed with a SAX cartridge to prevent false positives. A variety of shellfish species were surveyed for DA content, including Pecten maximus (king scallops), Chlamys opercularis (queen scallop), Mytilus edulis (blue mussels), Cancer pugaris (crab), and Ensis ensis (razor fish). The highest concentration of DA was 105 microg/g in Pecten maximus.

Comparison of paralytic shellfish toxin (PST) production by the dinoflagellates Alexandrium lusitanicum NEPCC 253 and Alexandrium tamarense NEPCC 407 in the presence and absence of bacteria

The ability of two Alexandrium species to produce paralytic shellfish toxins (PST) in laboratory culture following the generation of bacteria-free cultures was investigated. The dinoflagellates Alexandrium lusitanicum NEPCC 253 and Alexandrium tamarense NEPCC 407 were cultured in the presence of antibiotics and tested for residual bacteria. After treatment with a cocktail of streptomycin, ciprofloxacin, gentamicin and penicillin G, bacteria could not be detected in either of the treated Alexandrium cultures using 17 different solid and broth bacterial growth media, by epifluorescence microscopy with the dye Sybr green 1, or polymerase chain reaction amplification using universal eubacterial primers designed to target the 16S rRNA gene. Subsequent analysis of A. lusitanicum for PST using high performance liquid chromatography demonstrated that the growth rate and toxin profile remained similar in both bacteria-free and control cultures, although the quantity of toxins produced differed with the bacteria-free culture producing generally more of each compound and also having a greater toxin content in terms of saxitoxin equivalents. A. tamarense also retained similarities between the bacteria-free and control cultures in terms of growth rates and toxin profile, although in this instance, depending on the growth stage and the toxin, the control culture produced more of some toxins than the bacteria-free culture. The control culture was also more toxic in terms of saxitoxin equivalents than the axenic culture. These results suggest that bacteria can influence toxin production in laboratory cultures of Alexandrium species although the mechanisms remain unknown.

Biotransformations of paralytic shellfish toxins by bacteria isolated from bivalve molluscs

Due to the possibility that bacteria could be involved in the clearance of paralytic shellfish toxins (PST) from bivalve molluscs, investigations into which, if any, bacteria were able to grow at the expense of PST focused on several common shellfish species. These species were blue mussels, oysters, razor fish, cockles, and queen and king scallops. Bacteria associated with these shellfish were isolated on marine agar 2216 and characterized by their carbon utilization profiles (BIOLOG). Selected isolates from groups demonstrating 90% similarity were screened for their ability to metabolize a range of PST (gonyautoxins 1 and 4 [GTX 1/4], GTX 2/3, GTX 5, saxitoxin, and neosaxitoxin) using a novel screening method and confirming its results by high-performance liquid chromatography. Results suggest that molluscan bacteria have different capacities to utilize and transform PST analogues. For example, isolates M12 and R65 were able to reductively transform GTX 1/4 with concomitant production of GTX 2/3, while isolate Q5 apparently degraded GTX 1/4 without the appearance of other GTXs. Other observed possible mechanisms of PST transformations include decarbamoylation by isolate M12 and sulfation of GTXs by isolates Q5, R65, M12, and C3. These findings raise questions as to the possible role of bacteria resident in the shellfish food transport system. Some researchers have suggested that the microflora play a role in supplying nutritional requirements of the host. This study demonstrates that bacteria may also be involved in PST transformation and elimination in molluscan species.

The prevalence of familial hypocalciuric hypercalcemia

Familial hypocalciuric hypercalcemia is said to be an extremely rare condition but is clinically important because it can be confused with primary hyperparathyroidism. The biochemical features of the two conditions are similar, but the former is benign while the latter can have serious clinical consequences with patients occasionally proceeding to parathyroidectomy. It is therefore important to differentiate accurately between the two. With this in mind it would be useful to know the prevalence of familial hypocalciuric hypercalcemia when considering the differential diagnosis of primary hyperparathyroidism. However, as far as we are aware, no estimate of the prevalence of this condition can be found in the literature. We describe how an estimate was made of the prevalence of familial hypocalciuric hypercalcemia in the west of Scotland. We estimate the prevalence to be 1 in 78,000 at least.

DXA body composition studies are not affected by extracellular water measurements using stable sodium bromide dilution

Body composition studies using dual energy x-ray absorptiometry (DXA) are being increasingly reported in the literature. When DXA body composition measurements are combined with body water studies, stable bromide is often administered to measure extracellular water. Bromine attenuates x-rays significantly more than soft tissue and so could affect DXA body composition analysis. DXA scans were performed on 26 adults (12 F, 14 M) before and after the intravenous injection of 3 g sodium bromide (NaBr). No significant differences were noted pre- and post-NaBr infusion for whole-body fat mass, fat-free soft tissue mass and bone mineral content. These findings were supported by a simple mathematical analysis of the likely effect of the sodium bromide infusion. This showed that when 3 g NaBr was introduced into the body, the effect on fat mass estimates was expected to be marginally less than the precision of the DXA technique.

Paralytic shellfish poisoning toxins induce xenobiotic metabolising enzymes in Atlantic salmon (Salmo salar)

Paralytic shellfish poisoning (PSP) toxins have been implicated as the causative agent of a number of fish kills. Exposure experiments indicate that fish are susceptible to PSPs by intraperitoneal (i.p.) and oral administration, while sampling of fish affected by toxic blooms reveals that these toxins can be accumulated. In spite of the potential impact to marine fisheries, little research has been conducted on the potential metabolism and detoxification of PSPs in marine fishes. Previous work by this group has shown that the xenobiotic metabolising enzyme (XME) cytochrome P-450 (CYP1A) is induced in Atlantic salmon (Salmo salar) following i.p. exposure to saxitoxin (STX). Salmon injected i.p. with sub-lethal doses of STX show a four- to eight-fold induction of hepatic CYP1A (as shown by ethoxyresorufin-O-deethylase activity) over controls after 96 h. Results presented here show that the phase II XME glutathione S-transferase (GST) is also induced in salmon following PSP exposure. Post smolts were exposed to three injections of PSPs (2 micrograms STXeq/kg) over 21 days. Injection of both STX and PSPs extracted from a toxic strain of dinoflagellate (Alexandrium fundyense, CCMP 1719) resulted in induction of hepatic GST, as measured by activity for 1-chloro 2,4-dinitrobenzene. Such inductions indicate a potential role for XMEs in PSP metabolism. Possible roles for other enzymes are also discussed.

Marine toxins

Seafood products are important both nutritionally and economically. Within Europe, some 12 billion Pounds of fishery products are consumed annually and an enormous variety of species are available. Although seafood is rarely implicated in food poisoning, compared to other food sources, it does provide some specific human health hazards unique to this particular resource. Generally, these are toxins from toxic microscopic algae which accumulate through the food-chain. The toxins can cause various neurological and gastrointestinal illnesses and, potentially, consumers are exposed from seafood produced within Europe, from imported products, or from seafood eaten while travelling abroad. The symptoms of illness which may be encountered, the source and mode of action of the toxins, and some emerging problems are described. European legislation aims to ensure the quality and safety of seafood products by prohibiting sale of some toxic species, setting toxin limits, requiring monitoring and controlling imports.

Modification of the standard method used in the United Kingdom for counting Escherichia coli in live bivalve molluscs

The standard method for counting Escherichia coli in live bivalve molluscs is labour intensive and takes three days to obtain a result. Modifications to the standard method were investigated in a collaborative trial conducted in five centres. No significant difference was found between results based on the presence of acid at 24 hours (h) in first stage tests and those based on the presence of acid and gas after 48 h (standard method). The use of the chromogenic medium BCIG (5-bromo-4-chloro-3-indolyl-beta-D glucuronide) agar incubated at 44 degrees C to confirm first stage tests was also found to give equivalent results to conventional confirmation tests. The preferred, modified method removes the presence of gas as a criterion of detection, uses a chromogenic agar medium to confirm the presence of E. coli, and gives results within 48 h. A distribution of simulated samples and selected strains of E. coli to other laboratories using the PHLS external quality assurance scheme for shellfish found no significant difference between results obtained by the standard and modified methods.

An interlaboratory study to find an alternative to the MPN technique for enumerating Escherichia coli in shellfish

Nine laboratories in eight countries tested 16 batches of common mussels (Mytilus edulis) over a 32 week period in order to find an alternative to the Most Probable Number (MPN) technique to enumerate E. coli. The alternatives investigated included the 3M Petrifilm system, the Merck Chromocult agar method and a Malthus conductance technique. The Petrifilm was found to be unsuitable and was subsequently dropped from the trial. After 669 analyses, a correlation of 0.83 was observed for log E. coli counts between the MPN and Chromocult methods and there was no significant evidence that either method tended to give higher readings than the other. The MPN was slightly better than the Chromocult method for repeatability but the Chromocult was slightly better for reproducibility. However, the observed differences are probably too small to be of practical importance. On the basis of these data therefore, the two methods appear equally suitable for E. coli enumeration in shellfish. There were poor correlations between these methods and the Malthus technique. A small but significant number of samples tested positive on the Malthus instrument but were recorded negative on the MPN and Chromocult tests. Subsequent analysis positively identified E. coli from these Malthus assays. After statistical analysis, errors were noted in both the MPN and Chromocult methods but it was found that there would be no statistical differences if the Chromocult agar were used as an alternative to the MPN technique.

Development of a bioassay employing the desert locust (Schistocerca gregaria) for the detection of saxitoxin and related compounds in cyanobacteria and shellfish

Monitoring paralytic shellfish toxins (PST) in shellfish and freshwater cyanobacteria is largely dependent on the mouse bioassay. An alternative assay was devised using the desert locust Schistocerca gregaria. The bioassay successfully identified the optimum extraction procedure for PST from cyanobacterial cells and was also suitable for screening acid extracts of shellfish flesh. These results demonstrate the potential of the locust bioassay for the routine screening of PST in a range of sample matrices.

Alteration of the circadian rhythm of intact parathyroid hormone and serum phosphate in women with established postmenopausal osteoporosis

Several studies have established that the circulating concentration of intact parathyroid hormone, PTH (1-84), over 24 h follows a circadian rhythm. The importance of this circadian rhythm is not known although some authors have detected alterations in the rhythm in metabolic bone disease and following dietary manipulation. We have studied the circadian rhythm of PTH (1-84) in 8 premenopausal women, 8 postmenopausal women with established osteoporosis and 8 postmenopausal women with no evidence of osteoporosis. Blood samples were obtained at 30-min intervals over a 24-h period and significant differences were found in the profiles of PTH (1-84) and serum phosphate in the three groups studied. Premenopausal women possessed a nocturnal/early morning increase in PTH (1-84) and phosphate (between 2200 and 0700 hours), as did postmenopausal women without osteoporosis. In postmenopausal women with osteoporosis the nocturnal increase in PTH (1-84) and serum phosphate was absent and PTH (1-84) decreased during the period 2200-0700 hours. A shift in acrophase is observed between premenopausal and postmenopausal women without osteoporosis. No acrophase was found in postmenopausal women with osteoporosis for either PTH (1-84) or serum phosphate. No circadian rhythm, acrophase or significant amplitude was observed in serum adjusted calcium or ionized calcium in any group studied. Alterations in the circadian rhythms for PTH (1-84) and serum phosphate occur in patients with postmenopausal osteoporosis that suggest that normal dynamics of PTH (1-84) secretion may play a role in both calcium and phosphate metabolism and the bone remodelling process. Whether these changes are causative or a response to the pathology will require further investigation.

Attenuated neutrophil respiratory burst following acute hypoglycaemia in diabetic patients and normal subjects

The effects of insulin-induced hypoglycaemia on the neutrophil respiratory burst were investigated in six patients with type 1 diabetes and six non-diabetic control subjects. Plasma glucose reached similar nadirs in control subjects (0.9 +/- 0.1 mmol 1(-1); mean +/- SEM) and diabetic patients (1.2 +/- 0.2 mmol 1(-1)) (NS). The resting neutrophil respiratory burst was similar in control subjects (1.26 +/- 0.15 mV) and diabetic patients (1.03 +/- 0.18 mV) (NS). The neutrophil respiratory burst fell following hypoglycaemia in control subjects and diabetic patients to 0.38 +/- 0.05 mV (P < 0.001) and 0.54 +/- 0.09 mV (P < 0.05), respectively. This fall was significantly greater in control subjects (ANOVA; P < 0.001). Resting neutrophil counts were not significantly different in control subjects (3.2 +/- 0.3 x 10(9) 1(-1)) and diabetic patients (6.1 +/- 1.5 x 10(9) 1(-1)). Following hypoglycaemia, neutrophil numbers increased in control subjects and diabetic patients to 11.5 +/- 1.4 x 10(9) 1(-1) (P < 0.01) and 9.7 +/- 1.7 x 10(9) 1(-1) (P < 0.05), respectively. This increase was significantly greater in control subjects (ANOVA; P < 0.001). These results suggest that the neutrophil respiratory burst is suppressed in response to hypoglycaemia and that this phenomenon is more pronounced in non-diabetic subjects.

Evidence for production of paralytic shellfish toxins by bacteria associated with Alexandrium spp. (Dinophyta) in culture

A substantial proportion of bacteria from five Alexandrium cultures originally isolated from various countries produced sodium channel blocking (SCB) toxins, as ascertained by mouse neuroblastoma assay. The quantities of SCB toxins produced by bacteria and dinoflagellates were noted, and the limitations in comparing the toxicities of these two organisms are discussed. The chemical nature of the SCB toxins in selected bacterial isolates was determined as paralytic shellfish toxins by pre- and postcolumn high-performance liquid chromatography, capillary electrophoresis-mass spectrometry, and enzyme immunoassay.

Formulary management of drugs for cancer-associated hypercalcaemia

Hypercalcaemia associated with cancer is seen not infrequently in hospital practice and can be a source of considerable morbidity. Over the past decade, our understanding of the pathogenesis of this syndrome has advanced, allowing improved treatment protocols. Because one of the principal abnormalities relates to an increase in bone resorption, antiresorptive agents such as calcitonin and the bisphosphonates have been shown to be of value. In the medium to longer term, the bisphosphonates -particularly pamidronic acid[pamidronate;aminohydroxypropylidene bisphosphonate (APD)] and clodronic acid [clodronate; dichloromethyl bisphosphonate (Cl2MDP)]¿ appear to be more efficacious in terms of their calcium-lowering effect than calcitonin, and also appear to be associated with fewer adverse effects than most other agents. However, the importance of energetic re-expansion of the extracellular space with 0.9% sodium chloride before bisphosphonate therapy is extremely important. Cancer-associated hypercalcaemia, especially with squamous cancer, is often associated with the production of parathyroid hormone-related protein (PTHrP). Where this is the case, it usually reflects the presence of more advanced disease with shortened life expectancy, and poorer response to calcium-lowering therapy. Multiple treatments with larger doses of bisphosphonate may be required for these patients.

Neutrophil bactericidal function in diabetes mellitus: evidence for association with blood glucose control

Neutrophil bactericidal activity was assessed in patients with type 1 (n = 45) and Type 2 diabetes mellitus (n = 68) and non-diabetic control subjects (n = 40) by measurement of whole blood chemiluminescence. Though chemiluminescence values tended to be highest in the non-diabetic subjects these differences were not statistically significant (mean +/- SD) (2.73 +/- 1.65 mV (controls), 2.33 +/- 1.41 mV (Type 1 diabetes) and 2.38 +/- 1.12 mv (Type 2 diabetes), F = 1.12, p = 0.33). Significant negative correlations were evident, however, in patients with both Type 1 and Type 2 diabetes between chemiluminescence and glycated haemoglobin (rs = -0.35, p = 0.005 (Type 1), rs = -0.45, p = 0.002 (Type 2), fructosamine (rs = -0.36, p = 0.003 (Type 1), r = -0.42, p = 0.004 (Type 2)), and random blood glucose (rs 0 -0.25, p = 0.04 (Type 1), rs = -0.48, p = 0.001 (Type 2)). Changes in whole blood chemiluminescence in a further group of 10 patients with Type 2 diabetes mellitus commenced on insulin therapy were followed for 21 days. Serum fructosamine concentrations fell significantly over this time (524 +/- 58 mumol l-1 to 405 +/- 47 mumol l-1, p < 0.001), however, although chemiluminescence values tended to rise these changes were not statistically significant (1.01 +/- 0.38 mV to 1.60 +/- 0.91 mV, S = 4.24, df = 5, p = 0.52). These results suggested that impaired neutrophil bactericidal function is associated with poor blood glucose control. While it is likely that neutrophil bactericidal function will improve as blood glucose control improves, further studies are required both to confirm this and to demonstrate a reduction in the incidence of clinical bacterial infection.

Changes in calciotrophic hormones and biochemical markers of bone turnover in normal human pregnancy

Plasma concentrations of parathyroid hormone-related protein (PTHrP), parathyroid hormone, alkaline phosphatase, osteocalcin and albumin-adjusted calcium were measured along with nephrogenous cyclic adenosine monophosphate (NcAMP) in 10 normal women longitudinally through pregnancy. In addition, an assessment of bone resorption was made in these same subjects by the measurement in true fasting urine specimens of the calcium/creatinine ratio (Ca/Cr), hydroxyproline/creatinine ratio (HP/Cr), pyridinoline/creatinine ratio (Pyr/Cr) and deoxypyridinoline/creatine ratio (Dpyr/Cr). The PTHrP level rose through pregnancy from (mean +/- SEM) 0.8 +/- 0.2 pmol/l in the first trimester to 2.7 +/- 0.2 pmol/l 6 weeks postpartum (p < 0.0001). Serum alkaline phosphatase rose from 94 +/- 8 U/l (first trimester) to 347 +/- 25 U/l at term (p < 0.0001). A significant positive correlation was evident between PTHrP and alkaline phosphatase up to term (r = 0.44, p < 0.005). Parathyroid hormone concentrations remained unchanged during pregnancy but rose significantly postpartum from 1.8 +/- 0.2 pmol/l (first trimester) to 3.1 +/- 0.5 pmol/l (p < 0.0001). Similarly, osteocalcin, a marker of bone formative activity, remained unchanged through pregnancy but rose significantly at 6 weeks after delivery to 0.38 +/- 0.05 nmol/l from 0.19 +/- 0.03 nmol/l (first trimester) (p = 0.019). No significant change was noted in serum-adjusted calcium or NcAMP, either through pregnancy or at the postpartum assessment. Fasting urinary Ca/Cr fell through pregnancy from 0.70 +/- 0.11 (first trimester) to a nadir of 0.19 +/- 0.04 6 weeks postpartum (p = 0.007).(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokine and growth factor expression in Paget's disease: analysis by reverse-transcription/polymerase chain reaction

We investigated expression of several cytokines and growth factors in explants of Pagetic and non-Pagetic bone samples using the technique of reverse-transcription/polymerase chain reaction (RT/PCR). Transcripts for IL-1 alpha and IL-1 beta, TNF-alpha, TNF-beta, IL-6, basic fibroblast growth factor (bFGF), transforming growth factor beta (TGF-beta) and insulin-like growth factor-I (IGF-I) were found to a variable degree in both Pagetic and non-Pagetic bone samples, but there was no significant difference in the patterns of expression for these factors in Pagetic bone (n = 18) as compared with non-Pagetic bone (n = 51). There was furthermore, no significant difference in the patterns of expression for the various factors studied when patients were subdivided into mild and severe categories of disease activity using markers of bone formation (serum alkaline phosphatase) or bone resorption (osteoclast counts on adjacent biopsy specimens). Although IL-6 and IL-1 have previously been implicated as bone resorbing factors in Pagetic bone, 40% of our patients with severe disease had not detectable IL-6 transcripts, 70% had no detectable IL-1 alpha transcripts and 50% no IL-1 beta transcripts. We conclude that patterns of expression for cytokine and growth factor mRNAs are not disturbed in Paget's disease. Although we cannot exclude the possibility that post-transcriptional processing of the mRNAs may differ in Pagetic and normal bone cells, our data raise the possibility that the abnormalities of bone turnover which are characteristic of active Paget's disease may be due to local elaboration of other, possibly novel osteotropic factors, which stimulate bone formation and resorption.

Association of severe haemophilia A with osteoporosis: a densitometric and biochemical study

Following a femoral neck fracture and vertebral compression fractures in two patients with severe haemophilia A, bone density and turnover were measured in 19 males with severe haemophilia A (all HIV negative, 18/19 hepatitis C antibody positive) and in 19 age/sex matched controls. Bone density at the lumbar spine (L2-4), measured by dual energy X-ray absorptiometry, was significantly lower in the haemophiliac patients (HPs) at (mean +/- SEM) 1.109 +/- 0.042 g/cm2 vs. 1.234 +/- 0.027 in controls; p = 0.018. Femoral neck density was also lower at 0.877 +/- 0.034 g/cm2 (HPs) vs. 1.067 +/- 0.032; p < 0.0005. No significant differences were evident between the groups for serum calcium, parathyroid hormone, luteinizing hormone, follicle-stimulating hormone or 1,25 dihydroxyvitamin D3, nor for fasting urinary hydroxyproline, pyridinoline or deoxypyridinoline excretion. Serum total alkaline phosphatases was elevated in HPs at 200 +/- 10 U/l vs. 158 +/- 8; p = 0.004. Similarly, gamma-glutamyl transferase was elevated at 42 +/- 7 U/l (HPs) vs. 20 +/- 2; p = 0.007. Serum total testosterone and sex-hormone-binding globulin (SHBG) were higher in HPs at 26 +/- 2.5 nmol/l vs. 17.4 +/- 1.6 (p = 0.009) and 56 +/- 6 nmol/l vs. 27 +/- 3 (p = 0.0005), respectively. Free androgen index, however, was lower in HPs at 44 +/- 5 vs 69 +/- 7; p = 0.008. These results suggest significant osteopenia associated with haemophilia A. This may be partly due to liver dysfunction in HPs, but other factors, e.g. relative immobilization, may also be relevant.

Acute effects of intravenous 1 alpha-hydroxycholecalciferol on parathyroid hormone, osteocalcin and calcitriol in man

The acute effects of a single intravenous injection of 2 micrograms of 1 alpha-hydroxycholecalciferol (alfacalcidol) were studied for a 24-h period in six normal males (mean age 33 years), six women with primary hyperparathyroidism (mean age 72 years) and six women with established osteoporosis (mean age 63 years). In all three groups, serum calcitriol levels rose to a peak 2-3 h after administration of alfacalcidol. Basal levels were highest in the primary hyperparathyroidism group at (mean +/- SEM) 81 +/- 2 vs 62 +/- 12 (normal males) (p < 0.05) and 56 +/- 5 pmol/l (osteoporosis) (p < 0.01). Highest peak levels were found also in the primary hyperparathyroidism group at 150 +/- 15 vs 114 +/- 15 (normal males) (p < 0.05) and 127 +/- 15 pmol/l (osteoporosis) (p < 0.01). The rise in calcitriol was higher in the primary hyperparathyroidism group than either the normal males or osteoporotic patients (p < 0.05). No significant differences were evident in basal serum calcidiol concentrations among the three treatment groups. As might be expected, highest basal concentrations of parathyroid hormone (PTH), serum calcium and serum osteocalcin were noted in the primary hyperparathyroid group (PTH: 17.1 +/- 7.7 vs 1.9 +/- 0.5 (normal males) (p < 0.01) and 2.1 +/- 0.3 pmol/l (osteoporosis) (p < 0.01); calcium: 3.06 +/- 0.08 vs 2.50 +/- 0.02 (normal males) (p < 0.01) and 2.43 +/- 0.02 mmol/l (osteoporosis) (p < 0.01); osteocalcin: 1.10 +/- 0.08 vs 0.56 +/- 0.16 (normal males) (p < 0.05) and 0.53 +/- 0.21 nmol/l (osteoporosis) (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Mineralisation defects with pamidronate therapy for Paget's disease

Bone biopsy samples were taken from 20 patients with Paget's disease before and after intravenous pamidronate therapy. In 10 patients given 180 or 360 mg during 6 or 9 weeks, bone turnover decreased as measured biochemically and histologically, but osteomalacia developed in 1 patient and mineralisation defects in 3. 10 other patients received 45 mg every 3 months for 1 year. Bone turnover decreased biochemically but not histologically, and osteoid thickness increased, suggesting impaired mineralisation. Despite overall efficacy, pamidronate has a narrow therapeutic range between resorption inhibition and mineralisation defects. Short courses given to achieve biochemical remission should be administered with caution.

Effect of phosphate concentration on production of tetrodotoxin by Alteromonas tetraodonis

Tetrodotoxin production by Alteromonas tetraodonis occurred during the stationary phase of growth and was regulated by phosphate concentration; toxin production was repressed if phosphate was added at the onset of stationary phase and was over 100-fold greater in phosphate-limited cultures than in cultures in which phosphate was not limiting.

Central nervous system histiocytosis X--imaging and responses to chemotherapy

Histiocytosis X is the term first coined by Lichtenstein in 1953 to describe a heterogeneous group of disorders which is considered now to include Hand-Schuller-Christian disease, Letterer-Siwe disease and Eosinophilic Granuloma of bone. Gagel, in 1941, first described involvement of the central nervous system (CNS) in Histiocytosis X--in this case the hypothalamus and posterior pituitary were the areas principally affected. CNS involvement outwith these areas is rare, generally difficult to diagnose, and little information on treatment is available. In this case we describe a man with cranial histiocytosis X who was treated with intrathecal and systemic chemotherapy and cranial irradiation, and we comment upon the value of magnetic resonance imaging (MRI) in this condition.

Paget's disease of bone

In this review, recent studies on the etiology and pathogenesis of Paget's disease, with particular attention to the apparent familial clustering of cases and the possibility of a causal role for viral infection, are discussed. The role of biochemical markers of bone turnover is explored, as well as the value of imaging in confirming the diagnosis, monitoring the effects of therapy, and assessing complications. The bisphosphonates are widely used in the treatment of Paget's disease; experience with newer, more potent second- and third-generation bisphosphonates, as well as potential future roles for calcitonin, are described. Studies on some of the orthopedic effects of Paget's disease are also presented.

A comparison of 10 MHz ultrasound and 201-thallium/99m-technetium subtraction scanning in primary hyperparathyroidism

Both high resolution (10 MHz) ultrasound and 201-thallium/99m-technetium subtraction scanning (Tl/Tc) were carried out preoperatively in 25 patients with primary hyperparathyroidism. Operative findings were the standard against which these two imaging methodologies were compared. Tl/Tc scanning showed a sensitivity of 42% and a specificity of 97%. By comparison, sensitivity of ultrasound was 38% and specificity 89%. Both techniques were positive together in nine instances and correctly localized the parathyroid adenoma in eight of these. In 44% of cases, however, both methods together failed to localize any abnormal parathyroid tissue. The ability of these modalities to localize abnormal parathyroid tissue correctly tended to vary with gland size. Where both ultrasound and Tl/Tc scans were negative, median gland size was smaller at 170 mg (range 50-2,500 mg), compared with where Tl/Tc scanning was correct (750 mg, 150-6,820 mg; P < 0.03), ultrasound was correct (960 mg, 100-6,820 mg; P < 0.03) and both techniques together were correct (980 mg, 600-6,820 mg; P = 0.002). These results suggest that neither Tl/Tc scanning or ultrasound has sufficient sensitivity or specificity to be used routinely in the preoperative evaluation of patients with primary hyperparathyroidism.

Coincidental occurrence of primary hyperparathyroidism and cancer-associated hypercalcaemia in a middle-aged man

Primary hyperparathyroidism (PHPT) is found not uncommonly in patients with cancer. In this report, however, we describe a patient where both humoral hypercalcaemia of malignancy and PHPT were present coincidentally. A 47-year-old man was found to have PHPT due to parathyroid hyperplasia. Serum parathyroid hormone (PTH) levels, which were elevated before parathyroidectomy, were undetectable post-operatively; however, hypercalcaemia persisted. Nephrogenous cyclic adenosine monophosphate was elevated along with this undetectable PTH, indicative of the presence of a PTH-like factor in the serum. This was confirmed by the finding of an elevated level of PTH-related protein (PTHrP) in plasma (9.1 pmol/l, normal < 2.6 pmol/l). Secondary carcinoma was identified in a lesion in the region of the manubrium sternii. This stained positively for PTHrP by immunocytochemistry and PTHrP messenger RNA was detected by in-situ hybridization. This case illustrates the value of sensitive PTH assays in distinguishing PHPT from other causes of hypercalcaemia and also shows the importance of considering primary hyperparathyroidism in the differential diagnosis of the patient with cancer and hypercalcaemia.

Clinical and laboratory studies of a new immunoradiometric assay of parathyroid hormone-related protein

Parathyroid hormone-related protein (PTHrP) was measured in plasma by a new immunoradiometric assay (IRMA) from Nichols Institute. The assay is specific for PTHrP and shows excellent parallelism when measuring keratinocyte fluid, samples with high PTHrP content, and PTHrP-supplemented plasma. A precision profile established the assay detection limit at 0.7 pmol/L. PTHrP was unstable in plasma, but the degradation rate was patient-specific. Because delay in separation resulted in loss of PTHrP immunoreactivity, samples were collected into tubes containing protease inhibitors (aprotinin, leupeptin, pepstatin, and EDTA) and separated within 30 min. Among normal subjects, 78% had PTHrP values greater than the detection limit; the reference range established was < 0.7-2.6 pmol/L. Of patients with hypercalcemia associated with malignancy, 46% had PTHrP > 2.6 pmol/L. PTHrP was increased in patients with breast (73%), genitourinary (64%), or lung (46%) malignancy but was rarely above normal in patients with hematological (29%) or gastrointestinal (33%) malignancy. PTHrP and nephrogenous cyclic adenosine monophosphate (NcAMP) were strongly correlated (r = 0.63, P < 0.01) in 37 patients with PTHrP values greater than the detection limit, but 8 patients had PTHrP and parathyroid hormone [PTH(1-84)] values below the limit of detection with inappropriate or increased NcAMP. Five of these eight patients had small cell carcinoma of lung. These patients may have secreted a factor that is not detected by the IRMAs of PTHrP or PTH used in this study but that produces hypercalcemia by means of cAMP-mediated mechanisms.

An evaluation of bone density and turnover in premenopausal women with type 1 diabetes mellitus

Measurement of bone density and turnover was assessed in 20 premenopausal females with Type 1 diabetes mellitus and 27 age-sex-matched controls. Measurement was made of spinal (L2-4) and neck of femur bone density by dual-energy X-ray absorptiometry. L2-4 density was significantly higher in the diabetic patients compared with controls (1.224 +/- 0.021 g cm-2 vs. 1.161 +/- 0.020 g cm-2: p = 0.016). No significant difference was noted between the groups in neck of femur density. Measurement of bone formation was assessed by serum alkaline phosphatase and bone resorption by fasting urinary hydroxyproline/creatinine ratio. Alkaline phosphatase was significantly higher in the diabetic patients (185 +/- 16 Ul-1 vs 135 +/- 10 Ul-1: p < 0.01) as was hydroxyproline/creatinine ratio (0.028 +/- 0.003 vs 0.017 +/- 0.002: p = 0.002). No significant correlation was found between L2-4 density and glycated haemoglobin, duration of diabetes or daily dose of insulin taken. These data suggest that osteopenia is not associated with Type 1 diabetes mellitus; however these patients do have evidence of increased bone turnover and may therefore be at risk of osteoporosis in later life, particularly after the menopause.

Clinical and laboratory studies of a new immunoradiometric assay of parathyroid hormone-related protein

Parathyroid hormone-related protein (PTHrP) was measured in plasma by a new immunoradiometric assay (IRMA) from Nichols Institute. The assay is specific for PTHrP and shows excellent parallelism when measuring keratinocyte fluid, samples with high PTHrP content, and PTHrP-supplemented plasma. A precision profile established the assay detection limit at 0.7 pmol/L. PTHrP was unstable in plasma, but the degradation rate was patient-specific. Because delay in separation resulted in loss of PTHrP immunoreactivity, samples were collected into tubes containing protease inhibitors (aprotinin, leupeptin, pepstatin, and EDTA) and separated within 30 min. Among normal subjects, 78% had PTHrP values greater than the detection limit; the reference range established was &lt; 0.7-2.6 pmol/L. Of patients with hypercalcemia associated with malignancy, 46% had PTHrP &gt; 2.6 pmol/L. PTHrP was increased in patients with breast (73%), genitourinary (64%), or lung (46%) malignancy but was rarely above normal in patients with hematological (29%) or gastrointestinal (33%) malignancy. PTHrP and nephrogenous cyclic adenosine monophosphate (NcAMP) were strongly correlated (r = 0.63, P &lt; 0.01) in 37 patients with PTHrP values greater than the detection limit, but 8 patients had PTHrP and parathyroid hormone [PTH(1-84)] values below the limit of detection with inappropriate or increased NcAMP. Five of these eight patients had small cell carcinoma of lung. These patients may have secreted a factor that is not detected by the IRMAs of PTHrP or PTH used in this study but that produces hypercalcemia by means of cAMP-mediated mechanisms.

Factors predicting the acute effect of pamidronate on serum calcium in hypercalcemia of malignancy

In this study we retrospectively reviewed results of the first 9 days of treatment with pamidronate at doses of 30 mg (n = 13), 45 mg (n = 9), and 90 mg (n = 13) in an attempt to see what factors influenced the response of serum calcium to pamidronate. The nadir of serum calcium obtained post treatment was correlated with pretreatment levels of nephrogenous cyclic adenosine monophosphate (NcAMP), the renal tubular threshold for phosphate reabsorption (TmPO4), and the renal tubular threshold for calcium reabsorption (TmCa). Using the post treatment serum calcium levels, patients were divided into "good" and "poor" responders depending on whether a normal serum calcium was obtained. Pretreatment NcAMP was significantly correlated with the magnitude of the response of serum calcium (r = 0.45, P = 0.0001). Pretreatment NcAMP was significantly higher in the poor responders (mean +/- SEM): 65.0 +/- 9.4 nmol/liter GF (poor responders) versus 29.6 +/- 6.3 (good responders), P = 0.004. NcAMP as a predictor of the acute response of serum calcium showed a sensitivity of 93% and a specificity of 72%. Pretreatment TmPO4 was negatively correlated with the serum calcium response post treatment (r = -0.41, P = 0.003). However, though TmPO4 tended to be lower in the poor responders, this was not statistically significant [0.65 mmol/liter GF +/- 0.09 (poor responders) versus 0.76 mmol/liter GF +/- 0.06 (good responders)]. As a predictor of the acute response of serum calcium, TmPO4 was less good with a sensitivity of 70% and specificity of 58%. No significant correlation was present between TmCa and the serum calcium response.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravenous pamidronate in the treatment of osteoporosis associated with corticosteroid dependent lung disease: an open pilot study

BACKGROUND

Bisphosphonates have been shown to be effective agents in the treatment of postmenopausal osteoporosis. Because corticosteroid associated osteoporosis is often associated with increased bone turnover, the effect of intermittent intravenous infusions of pamidronate on this condition has been investigated.

METHODS

Seventeen patients (five male) with chronic corticosteroid dependent lung disease (15 asthma, two sarcoidosis) were treated with infusions of 30 mg pamidronate once every three months for one year. These patients had been taking an average of 14 (range 7.5-40) mg prednisolone a day for an average of 14 (range 3-30) years. Bone density measurements, by dual energy x ray absorptiometry, and radiography of the dorsolumbar spine were carried out before and one year after treatment. Bone formation was assessed by measurement of serum alkaline phosphatase and bone resorption by measurement of the fasting urinary hydroxyproline: creatinine ratio at the same time as densitometry and radiography were performed.

RESULTS

Pretreatment density of L2-4 and the neck of the femur was significantly lower in these patients compared with a cohort of 100 age and sex matched controls (L2-4 (mean (SEM)): 0.906 (0.050) g/cm2 v 1.142 (0.016) g/cm2; neck of femur: 0.793 (0.030) g/cm2 v 0.936 (0.013)) g/cm2. After treatment there was a significant fall in serum alkaline phosphatase activity from (mean (SEM)) 220 (16) U/1 to 174 (9) U/1 (normal 80-280 U/1) and in the fasting urinary hydroxyproline:creatinine ratio from (mean (SEM) 0.040 (0.006) to 0.024 (0.003) (normal < 0.033). A significant rise was noted in L2-4 density to 0.927 (0.047) g/cm2; mean rise of 3.4%). No change was noted in density of the neck of the femur.

CONCLUSIONS

Intermittent infusions of intravenous pamidronate would seem to be effective in both reducing turnover of bone and increasing bone density in corticosteroid induced osteoporosis associated with chronic lung disease. Longer term controlled studies are indicated.

A tissue culture assay for direct detection of sodium channel blocking toxins in bacterial culture supernates

A quantitative assay for sodium channel blocking toxins such as tetrodotoxin and saxitoxin has been developed for use with a microtitre plate reader. Mouse neuroblastoma cells, which die rapidly in the presence of ouabain and veratridine, were protected by tetrodotoxin; surviving cells were detected by their uptake of the vital dye Neutral red which was quantified with a microtitre plate reader at 540 nm. A sigmoidal dose response curve was obtained and tetrodotoxin concentrations were readily measured over the range 10 nM to 500 nM (3.2-160 ng/ml). With this method, sodium channel blocking toxins were detected directly, without processing or concentration, in culture supernates of several marine bacteria, including Shewanella alga, Alteromonas tetraodonis, Listonella (Vibrio) pelagia, V. alginolyticus, V. anguillarum and V. tubiashi. Culture supernates of Shewanella alga contained up to 510 ng/ml of sodium channel blocking toxin (using tetrodotoxin as a standard).