The contribution of bone loss to postmenopausal osteoporosis

We have addressed the relative importance of peak bone mass and subsequent rate of loss in determining postmenopausal women's bone mass in old age, by examining longitudinal measurements of radial mid-shaft bone mass on various samples of healthy white postmenopausal women. Using both the variance estimate of age-specific rates of bone loss and the population variance in bone mass, we determined that rates of loss could contribute importantly to future bone mass. However, since we found a small negative correlation between initial bone mass and rate of loss, it was necessary to estimate the effect of bone loss as the complement of the contribution of initial bone mass. We found that the influence of bone loss (relative to initial bone mass) increases as the women age, such that by about age 70, the contribution of initial bone mass and rate of loss approached equality. However, estimated rates of bone loss were not very stable over time, so it was difficult to identify long-term fast-losers. We conclude that the rate of postmenopausal bone loss is an important contributor to osteoporosis at old age, but it is difficult to identify long-term fast-losers, thereby reducing the clinical value of assessments of rates of change in bone mass early in the postmenopause.     

The NAP prism

The optics of the NAP prism are described. This is a prism that is produced commercially in "NAP glasses," which are marketed by the Sakura Company of Japan. It deflects a beam through about 90 degrees while keeping the image erect. Rays are both reflected and refracted, leading to some color fringing. The condition for zero color fringing is explored and the corresponding angle of deviation is calculated. The effects of prism apex angles on beam deviation angle and field of view are also investigated. The results show that the requirement for zero color fringing gives a small field of view but if some color fringing is tolerated, a larger field of view can be obtained.     

A comparison of the haemodynamic and hormonal effects of low and conventional dose cyclopenthiazide in normal volunteers

Summary In this study we compared low (125 g) and conventional (500 g) doses of cyclopenthiazide on the renin angiotensin system, plasma and extracellular fluid volumes and the pressor responsiveness to angiotensin II since we have previously shown that the two doses have the same antihypertensive effect but different effects on plasma renin activity.Following a two week placebo run-in period, 8 healthy male volunteers received 125 g or 500 g of cyclopenthiazide for 2 treatment periods of 4 weeks as part of a double blind, 2-part crossover study with treatment periods separated by a 4-week placebo washout phase. Measurements were made on two study days at the beginning and end of the active treatment periods. On the first day serum potassium, plasma renin activity and plasma angiotensin II levels were measured after a 1 h period of supine rest. Plasma and extracellular fluid volumes were also measured after appropriate equilibration times. The blood pressure responses to angiotensin II were assessed on day 2.The 500 g dose of cyclopenthiazide had a greater effect than the 125 g dose on plasma renin activity, serum potassium, angiotensin II levels and extracellular fluid volumes. Neither drug had any effect on plasma volume or the responsiveness to infused angiotensin II.Low dose cyclopenthiazide failed to increase angiotensin II levels, contract body fluid volumes or attenuate vascular reactivity in normotensive volunteers.     

Andrology: Relationship between stimulated hyperactivated motility of human spermatozoa and pregnancy rate in donor insemination: a preliminary report

The proportion of spermatozoa exhibiting the vigorous motilitybehaviour termed ’hyperactivation‘ (HA) has beenshown to be increased following removal of seminal plasma andstimulation with chemical agents such as pentoxifylline. Theaim of this study was to examine the relationship between theproportion of HA in cryopreserved semen samples from sperm donorsand the corresponding pregnancy rates achieved by donor insemination.Cryopreserved samples from 20 men were incubated in the presenceor absence of 3 mM pentoxifylline for 1 h and the %HA determinedin each sample. The relationship between pregnancy rate, theproportion of HA spermatozoa in control and pentoxifyllinetreatedgroups and the change in %HA following pentoxifylline treatment(HA) as well as the mean semen characteristics for each donor[sperm count, motility (%), motility index, normal morphology(%), post-thaw motility (%) and post-thaw motility index] wereexamined by logistic regression of the occurrence of clinicalpregnancy with each insemination. Both HA and mean post-thawmotility index were significantly related to pregnancy ratesand together accounted for 64% of the observed variation inpregnancy rates.     

Auditing the effect of experience and change on home parenteral nutrition related complications

A prospective record of all patients receiving home parenteral nutrition (HPN) in Tayside since 1980 has been used to audit the effect of experience and specific policy changes on HPN related complications. Total HPN related complications fell significantly over the years from 1.59 complications per treatment year during the initial 5 years of HPN experience to the current rate of 0.36 complications per treatment year. Specific policy changes, such as modification of the glucose concentration of feed, could also be shown to produce a significant benefit in the reduction of complications. Increasing experience with HPN results in a fall in complication rates, however, continuous audit of HPN is essential to determine the effect of policy changes on complication rates.     

Acute pouchitis and deficiencies of fuel

PURPOSE: Acute pouchitis is a troublesome complication after restorative proctocolectomy. Deficiency of fuel, especially short chain fatty acids (SCFA), produced by anaerobic bacterial fermentation of saccharides, is implicated in ulcerative and diversion colitis. Our hypothesis was that SCFA deficiency occurs in acute pouchitis, and correction of the deficiency is associated with resolution of pouchitis. METHODS: Thirty-two patients were studied, 10 with histologically confirmed acute pouchitis and 22 with healthy pouches. Stool concentrations of SCFA (acetic, propionic, butyric, and valeric acids) were determined by gas-liquid chromatography. Quantitative bacteriologic studies of stool were carried out, and four-quadrant pouch biopsies were assessed by a pathologist who was unaware of the clinical state. Patients with pouchitis were treated for six weeks with metronidazole and given dietary advice to increase their intake of fermentable saccharides. RESULTS: Stool concentrations of SCFA were significantly less in pouchitis patients compared with patients with healthy pouches (340 mol/g (range, 124–492) vs.93 (range, 44–136) P<0.01). No differences in anaerobic or aerobic counts were seen. Resolution of pouchitis was associated with a significant increase in SCFA, but anaerobic counts fell. CONCLUSION: Deficiency of SCFA is implicated in acute pouchitis Read at the meeting of The American Society of Colon and Rectal Surgeons, Orlando, Florida, May 8 to 13, 1994.     

Laboratory turnround time: closing the loop.

AIMS--To institute recommendations from a laboratory turnround time study; to evaluate audit methods; and to quantify improvements achieved. METHODS--Changes to result report distribution and specimen delivery were affected by posting results directly from the laboratory followed by the introduction of a twice daily courier service. Improvements were evaluated by repeating the turnround time audit described in an earlier report. Pre-, peri- and post-analytical turnround times were compared before and after changes had been instituted. RESULTS--Directly posting general practitioner (GP) results increased the percentage of reports which reached their destination within one and two days after they were generated from 13 to 29% and from 68 to 82%, respectively. Pre- and postanalytical times were superimposable before and after posting was started. Corresponding improvements to the satellite hospital service were from 25 to 78% and from 60 to 82%, respectively. The courier service shortened the median total turnround time from 50 to nine hours for GPs and from 69 to 18 hours for the satellite hospital. Fifty three per cent of GP reports and 21% of satellite hospital reports arrived on the same day as the sample was taken: 99% and 94%, respectively, had arrived by the next day. The number of analytically "old" samples which arrived the day after they had been taken, thus invalidating many results, fell from 25 to 3%. CONCLUSIONS--These audits of laboratory turnround time have been used to present a valid case for changes to laboratory transport and to quantify the improvements achieved. They produce consistent and repeatable results, which may also be used to monitor future performance, to assess further changes and to establish the cost-effectiveness of resources used.